U.S. patent number 6,613,308 [Application Number 09/877,734] was granted by the patent office on 2003-09-02 for pulmonary delivery in treating disorders of the central nervous system.
This patent grant is currently assigned to Advanced Inhalation Research, Inc.. Invention is credited to Raymond T. Bartus, Dwaine F. Emerich.
United States Patent |
6,613,308 |
Bartus , et al. |
September 2, 2003 |
Pulmonary delivery in treating disorders of the central nervous
system
Abstract
A method for treating a disorder of the central nervous system
includes administering to the respiratory tract of a patient a drug
which is delivered to the pulmonary system, for instance to the
alveoli or the deep lung. The drug is administered at a dose which
is at least about two-fold less than the dose required by oral
administration. Particles that include the drug can be employed.
Preferred particles have a tap density of less than about 0.4
g/cm.sup.3. In addition to the medicament, the particles can
include other materials such as, for example, phospholipids, amino
acids, combinations thereof and others.
Inventors: |
Bartus; Raymond T. (Sudbury,
MA), Emerich; Dwaine F. (Cranston, RI) |
Assignee: |
Advanced Inhalation Research,
Inc. (Cambridge, MA)
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Family
ID: |
27099159 |
Appl.
No.: |
09/877,734 |
Filed: |
June 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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665252 |
Sep 19, 2000 |
6514482 |
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Current U.S.
Class: |
424/45;
128/203.15; 424/46; 424/489; 514/220; 560/43; 514/567;
514/255.03 |
Current CPC
Class: |
A61P
25/00 (20180101); A61P 25/06 (20180101); A61P
11/00 (20180101); A61K 9/0075 (20130101); A61K
9/16 (20130101); A61K 9/008 (20130101); A61K
9/14 (20130101); A61P 25/16 (20180101); A61P
25/08 (20180101); A61P 25/22 (20180101); A61K
9/007 (20130101); A61P 25/24 (20180101); A61P
25/28 (20180101); A61K 31/4045 (20130101); A61P
25/18 (20180101) |
Current International
Class: |
A61K
9/72 (20060101); A61K 9/00 (20060101); A61K
9/14 (20060101); A61K 9/12 (20060101); A61K
009/12 (); A61K 009/14 (); A61K 009/72 () |
Field of
Search: |
;424/45,489,46
;514/220,252,567 ;128/203.15 ;560/43 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2152684 |
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Jun 1995 |
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CA |
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0496 307 |
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Jul 1992 |
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EP |
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61022019 |
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Jan 1986 |
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JP |
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WO 91/16882 |
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Nov 1991 |
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WO |
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WO 98/31346 |
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Jul 1998 |
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WO |
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WO 98/46245 |
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Oct 1998 |
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WO |
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WO 00/72827 |
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Dec 2000 |
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WO |
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WO 01/95874 |
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Dec 2001 |
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WO |
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Primary Examiner: Hartley; Michael G.
Assistant Examiner: Haghighatian; M.
Attorney, Agent or Firm: Hamilton, Brook, Smith &
Reynolds, P.C.
Parent Case Text
RELATED APPLICATION
This application is a Continuation-in-Part of U.S. patent
application Ser. No. 09/665,252, filed on Sep. 19, 2000, U.S. Pat.
No. 6,514,482, the entire contents of which are incorporated herein
by reference.
Claims
What is claimed is:
1. A method for treating Parkinson's disease comprising
administering to the respiratory tract of a patient in need of
treatment or rescue therapy a drug for treating Parkinson's disease
wherein the drug is administered in a dose that is at least about
two times less than that required by oral administration and
wherein delivery is to the pulmonary system.
2. The method of claim 1 wherein the drug is levodopa.
3. The method of claim 1 wherein the dose is between about two
times and about five times less than that required by oral
administration.
4. The method of claim 1 wherein the dose is between about two
times and about ten times less than that required by oral
administration.
5. The method of claim 1 wherein delivery is to the alveoli region
of the pulmonary system.
6. The method of claim 1 wherein administering is for rescue
therapy.
7. The method of claim 1 wherein administering is during ongoing
treatment.
8. The method of claim 1 wherein the drug is present in dry powder
particles.
9. The method of claim 8 wherein the drug is present in the dry
powder particles in an amount of at least 20 weight percent in the
drug containing particles.
10. The method of claim 8 wherein the drug is present in the dry
powder particles in an amount of at least 40 weight percent in the
drug containing particles.
11. The method of claim 8 wherein the drug is present in the dry
powder particles in an amount of at least 50 weight percent in the
drug containing particles.
12. The method of claim 8 wherein the particles have a tap density
of less than about 0.4 g/cm.sup.3.
13. The method of claim 8 wherein the particles have a mass median
aerodynamic diameter of less than about 5 microns.
14. The method of claim 8 wherein the particles have a mass median
geometric diameter greater than about 5 microns.
15. The method of claim 8 wherein the particles have a mass median
aerodynamic diameter of less than about 3 microns.
16. The method of claim 8 wherein the particles include a
phospholipid.
17. The method of claim 8 wherein the particles include a
multivalent salt.
18. The method of claim 8 wherein the particles are administered
via a dry powder inhaler.
19. The method of claim 18 wherein the dry powder inhaler is a
single dose breath activated dry powder inhaler.
20. The method of claim 1 further comprising co-administering at
least one additional agent wherein the drug and the agent are
present in the same formulation.
21. The method of claim 1 further comprising co-administering at
least one additional agent wherein the drug and the agent are
separately formulated.
22. The method of claim 21 wherein the drug and the agent are
blended together into a receptacle.
23. The method of claim 21 wherein the drug and the agent are
administered sequentially.
24. The method of claim 1 further comprising co-administering at
least one additional agent wherein the additional agent is
administered by conventional therapies.
Description
BACKGROUND OF THE INVENTION
Parkinson's disease is characterized neuropathologically by
degeneration of dopamine neurons in the basal ganglia and
neurologically by debilitating tremors, slowness of movement and
balance problems. It is estimated that over one million people
suffer from Parkinson's disease. Nearly all patients receive the
dopamine precursor levodopa or L-Dopa, often in conjunction with
the dopa-decarboxylase inhibitor, carbidopa. L-Dopa adequately
controls symptoms of Parkinson's disease in the early stages of the
disease. However, it tends to become less effective after a period
which can vary from several months to several years in the course
of the disease.
It is believed that the varying effects of L-Dopa in Parkinson's
disease patients is related, at least in part, to the plasma half
life of L-Dopa which tends to be very short, in the range of 1 to 3
hours, even when co-administered with carbidopa. In the early
stages of the disease, this factor is mitigated by the dopamine
storage capacity of the targeted striatal neurons. L-Dopa is taken
up and stored by the neurons and is released over time. However, as
the disease progresses, dopaminergic neurons degenerate, resulting
in decreased dopamine storage capacity. Accordingly, the positive
effects of L-Dopa become increasingly related to fluctuations of
plasma levels of L-Dopa. In addition, patients tend to develop
problems involving gastric emptying and poor intestinal uptake of
L-Dopa. Patients exhibit increasingly marked swings in Parkinson's
disease symptoms, ranging from a return to classic Parkinson's
disease symptoms, when plasma levels fall, to the so-called
dyskinesis, when plasma levels temporarily rise too high following
L-Dopa administration.
As the disease progresses, conventional L-Dopa therapy involves
increasingly frequent, but lower dosing schedules. Many patients,
for example, receive L-Dopa every two to three hours. It is found,
however, that even frequent doses of L-Dopa are inadequate in
controlling Parkinson's disease symptoms. In addition, they
inconvenience the patient and often result in non-compliance.
It is also found that even with as many as six to ten L-Dopa doses
a day, plasma L-Dopa levels can still fall dangerously low, and the
patient can experience very severe Parkinson's disease symptoms.
When this happens, additional L-Dopa is administered as
intervention therapy to rapidly increase brain dopamine activity.
However, orally administered therapy is associated with an onset
period of about 30 to 45 minutes during which the patient suffers
unnecessarily. In addition, the combined effects of the
intervention therapy, with the regularly scheduled dose can lead to
overdosing, which can require hospitalization. For example,
subcutaneously administered dopamine receptor agonist
(apomorphine), often requiring a peripherally acting dopamine
antagonist, for example, domperidone, to control dopamine-induced
nausea, is inconvenient and invasive.
Other medical indications involving the central nervous system
(CNS) require rapid delivery of a medicament such as but not
limited to epilepsy, panic attacks and migraines. For example,
about 2 million people in the USA suffer from some form of
epilepsy, with the majority receiving at least one of several
different anti-seizure medications. The incidence of status
epilepticus (the more serious form of epilepsy) is approximately
250,000. A significant number of patients also suffer from
so-called "cluster seizures", wherein an initial seizure forewarns
that a series of additional seizures will occur within a relatively
short time frame. By some reports, 75% of all patients continue to
experience seizures despite taking medication chronically. Poor
compliance with the prescribed medications is believed to be a
significant (albeit not sole) contributing factor. The importance
of controlling or minimizing the frequency and intensity of
seizures lies in the fact that incidence of seizures has been
correlated with neuronal deficits and is believed to cause loss of
neurons in the brain.
Despite chronic treatment, as many as 75% of all patients continue
to exhibit periodic seizures. The uncontrolled seizures occur in
many forms. In the case of "cluster seizures," one seizure serves
notice that a cascade has begun which will lead to a series of
seizures before the total episode passes. In certain patients,
prior to the onset of a severe seizure, some subjective feeling or
sign is detected by the patient (defined as an aura). In both
instances, an opportunity exists for these patients to
significantly reduce the liability of the seizure through "self
medication". While many patients are instructed to do so, the drugs
currently available to permit effective self medication are
limited.
Panic attacks purportedly affect at least about 2.5 million people
in this country alone. The disorder is characterized by acute
episodes of anxiety, leading to difficult breathing, dizziness,
heart palpitations and fear of losing control. The disorder is
believed to involve a problem with the sympathetic nervous system
(involving an exaggerated arousal response, leading to
overstimulation of adrenaline release and/or adrenergic neurons).
Current pharmacotherapy combines selective serotonin re-uptake
inhibitors (SSRIs), or other antidepressant medications, with the
concomitant use of benzodiazapines.
A limitation of the pharmacotherapies in current use is the delay
in the onset of efficacy at the beginning of treatment. Like
treatments for depression, the onset of action of the SSRIs
requires weeks rather than days. The resulting requirement for
continuous prophylactic treatment can, in turn, lead to significant
compliance problems rendering the treatment less effective.
Therefore, there is a need for rapid onset therapy at the beginning
of treatment to manage the anticipation of the panic attacks, as
well as a treatment for aborting any attacks as soon as possible
after their occurrence.
A pure vasogenic etiology/pathogenesis for migraine was first
proposed in the 1930s; by the 1980s, this was replaced by a
neurogenic etiology/pathogenesis, which temporarily won favor among
migraine investigators. However, it is now generally recognized
that both vasogenic and neurogenic components are involved,
interacting as a positive feedback system, with each continuously
triggering the other. The major neurotransmitters implicated
include serotonin (the site of action of the triptans), substance P
(traditionally associated with mediating pain), histamine
(traditionally associated with inflammation) and dopamine. The
major pathology associated with migraine attacks include an
inflammation of the dura, an increase in diameter of meningeal
vessels and supersensitivity of the trigeminal cranial nerve,
including the branches that enervate the meningeal vessels. The
triptans are believed to be effective because they affect both the
neural and vascular components of the migraine pathogenic cascade.
Migraines include Classic and Common Migraines, Cluster Headaches
and Tension Headaches.
Initial studies with sumatriptain showed that, when administered
intravenously (IV), a 90% efficacy rate was achieved. However, the
efficiency rate is only approximately 60% with the oral form
(versus 30% for placebo). The nasal form has proven to be highly
variable, requiring training and skill on the part of the patient,
which some of the patients do not seem to master. The treatment
also induces a bad taste in the mouth which many patients find
highly objectionable. There currently exists no clear evidence that
any of the recent, more selective 5HT1 receptor agonists are any
more efficacious than sumatriptan (which stimulates multiple
receptor subtypes; e.g., 1B, 1D, and 1F).
In addition to not providing adequate efficacy, current dosing of
triptans have at least two other deficiencies: (1) vasoconstriction
of chest and heart muscles, which produces chest tightness and pain
in some subjects; this effect also presents an unacceptable risk to
hypertensive and other CV patients, for whom the triptans are
contraindicated, and (2) the duration of action of current
formulations is limited, causing a return of headache in many
patients about 4 hours after initial treatment.
Rapid onset of a hypnotic would also be quite desirable and
particularly useful in sleep restoration therapy, as middle of
night awakening and difficulty in falling asleep again, once
awakened, is common in middle aged and aging adults.
Other indications related to the CNS, such as, for example, mania,
bipolar disorders, schizophrenia, appetite suppression, motion
sickness, nausea and others, as known in the art, also require
rapid delivery of a medicament to its site of action.
Therefore, a need exists for methods of delivery of medicaments
which are at least as effective as conventional therapies yet
minimize or eliminate the above-mentioned problems.
SUMMARY OF THE INVENTION
The invention relates to methods of treating disorders of the
central nervous system (CNS). More specifically the invention
relates to methods of delivering a drug suitable in treating a
disorder of the CNS to the pulmonary system and include
administering to the respiratory tract of a patient in need of
treatment particles comprising an effective amount of the
medicament. In one embodiment, the patient is in need of rapid
onset of the treatment, for instance in need of rescue therapy; the
medicament is released into the patient's blood stream and reaches
the medicament's site of action in a time interval which is
sufficiently short to provide the rescue therapy or rapid treatment
onset. In another embodiment, the invention is related to providing
ongoing, non-rescue therapy to a patient suffering with a disorder
of the CNS.
Disorders of the nervous system include, for example, Parkinson's
disease, epileptic and other seizures, panic attacks, sleep
disorders, migraines, attention deficit hyperactivity disorders,
Alzheimer's disease, bipolar disorders, obsessive compulsive
disorders and others.
The methods of the invention are particularly useful in the ongoing
treatment and for rescue therapy in the course of Parkinson's
disease. The drug or medicament employed in the methods of the
invention is a dopamine precursor or a dopamine agonist, for
example, levodopa (L-DOPA).
In one embodiment, the invention is related to a method for
treating Parkinson's disease includes administering to the
respiratory tract of a patient in need of treatment or rescue
therapy a drug for treating Parkinson's disease, e.g., L-Dopa. The
drug is delivered to the pulmonary system, for instance to the
alveoli region of the lung. In comparison to oral administration,
at least about a two fold dose reduction is employed. Doses
generally are between about two times and about ten times less than
the dose required with oral administration.
In other embodiments, a method for treating a disorder of the CNS
includes administering to the respiratory tract of a patient in
need of treatment a drug for treating the disorder. The drug is
administered in a dose which is at least about two times less than
the dose required with oral administration and is delivered to the
pulmonary system.
The doses employed in the invention generally also are at least
about two times less than the dose required with routes of
administration other than intravenous, such as, for instance,
subcutaneous injection, intramuscular injection, intra-peritoneal,
buccal, rectal and nasal.
The invention further is related to methods for administering to
the pulmonary system a therapeutic dose of the medicament in a
small number of steps, and preferably in a single, breath activated
step. The invention also is related to methods of delivering a
therapeutic dose of a drug to the pulmonary system, in a small
number of breaths, and preferably in a single breath. The methods
include administering particles from a receptacle which has a mass
of particles, to a subject's respiratory tract. Preferably, the
receptacle has a volume of at least about 0.37 cm.sup.3 and can
have a design suitable for use in a dry powder inhaler. Larger
receptacles having a volume of at least about 0.48 cm.sup.3, 0.67
cm.sup.3 or 0.95 cm.sup.3 also can be employed. The receptacle can
be held in a single dose breath activated dry powder inhaler.
In one embodiment of the invention, the particles deliver at least
about 10 milligrams (mg) of the drug. In other embodiments, the
particles deliver at least about 15, 20, 25, 30 milligrams of drug.
Higher amounts can also be delivered, for example the particles can
deliver at least about 35, 40 or 50 milligrams of drug.
The invention also is related to methods for the efficient delivery
of particles to the pulmonary system. In one embodiment, the
invention is related to delivering to the pulmonary system
particles that represent at least about 70% and preferably at least
about 80% of the nominal powder dose. In another embodiment of the
invention, a method of delivering a medicament to the pulmonary
system, in a single, breath-activated step, includes administering
particles, from a receptacle which has a mass of particles, to the
respiratory tract of a subject, wherein at least 50% of the mass of
particles is delivered.
Preferably, administration to the respiratory tract is by a dry
powder inhaler or by a metered dose inhaler. The particles of the
invention also can be employed in compositions suitable for
delivery to the pulmonary system such as known in the art.
In one embodiment, particles employed in the method of the
invention are particles suitable for delivering a medicament to the
pulmonary system and in particular to the alveoli or the deep lung.
In a preferred embodiment, the particles have a tap density which
is less than 0.4 g/cm.sup.3. In another preferred embodiment, the
particles have a geometric diameter, of at least 5 .mu.m (microns),
preferably between about 5 .mu.m and 30 .mu.m. In yet another
preferred embodiment, the particles have an aerodynamic diameter
between about 1 .mu.m and about 5 .mu.m. In another embodiment, the
particles have a mass median geometric diameter (MMGD) larger than
5 .mu.m, preferably around about 10 .mu.m or larger. In yet another
embodiment, the particles have a mass median aerodynamic diameter
(MMAD) ranging from about 1 .mu.m to about 5 .mu.m. In a preferred
embodiment, the particles have an MMAD ranging from about 1 .mu.m
tobout 3 .mu.m.
Particles can consist of the medicament or can further include one
or more additional components. Rapid release of the medicament into
the blood stream and its delivery to its site of action, for
example, the central nervous system, is preferred. In one
embodiment of the invention, the particles include a material which
enhances the release kinetics of the medicament. Examples of
suitable such materials include, but are not limited to, certain
phospholipids, amino acids, carboxylate moieties combined with
salts of multivalent metals and others.
In a preferred embodiment, the energy holding the particles of the
dry powder in an aggregated state is such that a patient's breath,
over a reasonable physiological range of inhalation flow rates is
sufficient to deaggregate the powder contained in the receptacle
into respirable particles. The deaggregated particles can penetrate
via the patient's breath into and deposit in the airways and/or
deep lung with high efficiency.
The invention has many advantages. For example, pulmonary delivery
provides on-demand treatment without the inconvenience of
injections. Selective delivery of a medicament to the central
nervous system can be obtained in a time frame not available with
other administration routes, in particular conventional oral
regimens. Thus, an effective dose can be delivered to the site of
action on the "first pass" of the medicament in the circulatory
system. By practicing the invention, relief is available to
symptomatic patients in a time frame during which conventional oral
therapies would still be traveling to the site of action. The
reduced doses employed in the methods of the invention result in a
plasma drug level which is equivalent to that obtained with the
oral dose. Blood plasma levels approaching those observed with
intravenous administration can be obtained. Dose advantages over
other routes of administration, e.g., intramuscular, subcutaneous,
intra-peritoneal, buccal, rectal and nasal, also can be obtained.
Furthermore, a therapeutic amount of the drug can be delivered to
the pulmonary system in one or a small number of steps or
breaths.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a plot representation of blood levels of L-Dopa in rats
following administration via oral gavage or direct administration
to the lungs measured by mass spectrometer.
FIG. 1B is a plot representation of blood levels of L-Dopa in rats
following administration via oral gavage or direct administration
to the lungs measured by HPLC.
FIG. 2A is a plot representation of blood L-Dopa levels in rats
following delivery orally or directly into the lungs.
FIG. 2B is a plot representation of striatal dopamine levels in
rats following delivery of L-Dopa orally or directly into the
lungs.
FIG. 3 is a plot representation of blood and striatal levels of
.sup.14 C following administration of .sup.14 C-L-Dopa either
orally or directly to the lungs.
FIG. 4 is a plot representation of plasma .sup.14 C levels in rats
following .sup.14 C-L-Dopa administration via oral (gavage),
tracheotomy or ventilator.
FIG. 5 is a plot representation of brain .sup.14 C levels in rats
following .sup.14 C-L-Dopa administration via oral (gavage),
tracheotomy or ventilator.
FIG. 6A is a bar graph showing absolute .sup.14 C-Carboplatin
levels in regions of the brain following intravenous (IV) and
pulmonary (lung) administration.
FIG. 6B is a bar graph showing relative .sup.14 C-Carboplatin
levels in regions of the brain following intravenous (IV) and
pulmonary (lung) administration.
FIG. 7A is a bar graph showing absolute .sup.14 C-Carboplatin
levels in animal organs following intravenous (IV) or pulmonary
(lung) administration.
FIG. 7B shows relative .sup.14 C-Carboplatin levels in animal
organs following intravenous (IV) or pulmonary (lung)
administration.
FIG. 8 is a plot representation showing plasma concentration of
L-Dopa vs. time following oral or pulmonary administration
(normalized for an 8 mg dose).
FIG. 9 is a plot representation showing plasma concentration of
ketoprofen vs. time for oral and pulmonary groups.
FIG. 10 is a plot representation showing plasma concentration of
ketoprofen vs. time for oral group
FIG. 11 is a plasma concentration of ketoprofen vs. time for
pulmonary group.
FIG. 12 is a plot showing RODOS curves for different powder
formulations that include L-DOPA.
FIGS. 13A and 13B are HPLC chromatograms that depict L-DOPA
recovery from powders (FIG. 13A) compared to a blank sample (FIG.
13B).
FIG. 14A depicts L-DOPA plasma levels following pulmonary (lung),
and oral routes.
FIG. 14B depicts L-DOPA plasma levels following pulmonary (lung),
oral and intravenous administration.
FIGS. 15A and 15B show results, respectively, of oral (p.o.) and
pulmonary (lung) L-DOPA on functional "placing task" in a rat model
of Parkinson's disease.
FIGS. 16A and 16B show results, respectively of oral (p.o.) and
pulmonary (lung) L-DOPA on functional "bracing task" in a rat model
of Parkinson's disease.
FIGS. 17A and 17B show results, respectively of oral (p.o.) and
pulmonary (lung) L-DOPA on functional akinesia task in a rat model
of Parkinson's disease.
FIG. 18 shows results of oral (p.o.) and pulmonary (lung) delivery
of L-DOPA on functional rotation in a rat model of Parkinson's
disease.
FIG. 19A depicts time to seizure onset after delivery of pulmonary
and oral alprazolam 10 minutes prior to PZT administration.
FIG. 19B depicts duration of seizure after delivery of pulmonary
and oral alprazolam 10 minutes prior to PZT administration.
FIG. 20A depicts time to seizure onset after delivery of pulmonary
and oral alprazolam 30 minutes prior to PZT administration.
FIG. 20B depicts duration of seizure after delivery of pulmonary
and oral alprazolam 30 minutes prior to PZT administration.
FIG. 21A depicts time to seizure onset for pulmonary alprazolam 10
and 30 minutes prior to PZT administration.
FIG. 21B depicts duration of seizure for pulmonary alprazolam 10
and 30 minutes prior to PZT administration.
DETAILED DESCRIPTION OF THE INVENTION
The features and other details of the invention, either as steps of
the invention or as combination of parts of the invention, will now
be more particularly described and pointed out in the claims. It
will be understood that the particular embodiments of the invention
are shown by way of illustration and not as limitations of the
invention. The principle feature of this invention may be employed
in various embodiments without departing from the scope of the
invention.
The invention is generally related to methods of treating disorders
of the CNS. In particular, the invention is related to methods for
pulmonary delivery of a drug, medicament or bioactive agent.
One preferred medical indication which can be treated by the method
of the invention is Parkinson's disease, in particular during the
late stages of the disease, when the methods described herein
particularly well suited to provide rescue therapy. As used herein,
"rescue therapy" means on demand, rapid delivery of a drug to a
patient to help reduce or control disease symptoms. The methods of
the invention also are suitable for use in patients in acute
distress observed in disorders of the CNS. In other embodiments,
the methods and particles disclosed herein can be used in the
ongoing (non-rescue) treatment of Parkinson's disease.
In addition to Parkinson's disease, forms of epileptical seizures
such as occurring in Myoclonic Epilepsies, including Progressive
and Juvenile; Partial Epilepsies, including Complex Partial,
Frontal Lobe, Motor and Sensory, Rolandic and Temporal Lobe; Benign
Neonatal Epilepsy; Post-Traumatic Epilepsy; Reflex Epilepsy;
Landau-Kleffner Syndrome; and Seizures, including Febrile, Status
Epilepticus, and Epilepsia Partialis Continua also can be treated
using the method of the invention.
Attention deficit/hyperactivity disorders (ADHD) also can be
treated using the methods and formulations of the invention.
Sleep disorders that can benefit from the present invention include
Dyssomnias, Sleep Deprivation, Circadian Rhythm Sleep Disorders,
Intrinsic Sleep Disorders, including Disorders of Excessive
Somnolence, Idiopathic Hypersomnolence, Kleine-Levin Syndrome,
Narcolepsy, Nocturnal Myoclonus Syndrome, Restless Legs Syndrome,
Sleep Apnea Syndromes, Sleep Initiation and Maintenance Disorders,
Parasomnias, Nocturnal Nyoclonus Syndrome, Nocturnal Paroxysmal
Dystonia, REM Sleep Parasomnias, Sleep Arousal Disorders, Sleep
Bruxism, and Sleep-Wake Transition Disorders. Sleep interruption
often occurs around 2 to 3 a.m. and requires treatment the effect
of which lasts approximately 3 to 4 hours.
Examples of other disorders of the central nervous system which can
be treated by the method of the invention include but are not
limited to appetite suppression, motion sickness, panic or anxiety
attack disorders, nausea suppressions, mania, bipolar disorders,
schizophrenia and others, known in the art to require rescue
therapy.
Medicaments which can be delivered by the method of the invention
include pharmaceutical preparations such as those generally
prescribed in the rescue therapy of disorders of the nervous
system. In a preferred embodiment, the medicament is a dopamine
precursor, dopamine agonist or any combination thereof. Preferred
dopamine precursors include levodopa (L-Dopa). Other drugs
generally administered in the treatment of Parkinson's disease and
which may be suitable in the methods of the invention include, for
example, ethosuximide, dopamine agonists such as, but not limited
to carbidopa, apomorphine, sopinirole, pramipexole, pergoline,
bronaocriptine. The L-Dopa or other dopamine precursor or agonist
may be any form or derivative that is biologically active in the
patient being treated.
Examples of anticonvulsants include but are not limited to
diazepam, valproic acid, divalproate sodium, phenytoin, phenytoin
sodium, cloanazepam, primidone, phenobarbital, phenobarbital
sodium, carbamazepine, amobarbital sodium, methsuximide,
metharbital, mephobarbital, mephenytoin, phensuximide,
paramethadione, ethotoin, phenacemide, secobarbitol sodium,
clorazepate dipotassium, trimethadione. Other anticonvulsant drugs
include, for example, acetazolamide, carbamazepine,
chlormethiazole, clonazepam, clorazepate dipotassium, diazepam,
dimethadione, estazolam, ethosuximide, flunarizine, lorazepam,
magnesium sulfate, medazepam, melatonin, mephenytoin,
mephobarbital, meprobamate, nitrazepam, paraldehyde, phenobarbital,
phenytoin, primidone, propofol, riluzole, thiopental, tiletamine,
trimethadione, valproic acid, vigabatrin. Benzodiazepines are
preferred drugs. Examples include, but are not limited to,
alprazolam, chlordiazepoxide, clorazepate dipotassium, estazolam,
medazepam, midazolam, triazolam, as well as benzodiazepinones,
including anthramycin, bromazepam, clonazepam, devazepide,
diazepam, flumazenil, flunitrazepam, flurazepam, lorazepam,
nitrazepam, oxazepam, pirensepine, prazepam, and temazepam.
Examples of drugs for providing symptomatic relief for migraines
include the non-steroidal anti-inflammatory drugs (NSAIDs).
Generally, parenteral NSAIDs are more effective against migraine
than oral forms. Among the various NSAIDs, ketoprofen is considered
by many to be one of the more effective for migraine. Its T.sub.max
via the oral route, however, is about 90 min. Other NSAIDs include
aminopyrine, amodiaquine, ampyrone, antipyrine, apazone, aspirin,
benzydamine, bromelains, bufexamac, BW-755C, clofazimine, clonixin,
curcumin, dapsone, diclofenac, diflunisal, dipyrone, epirizole,
etodolac, fenoprofen, flufenamic acid, flurbiprofen, glycyrrhizic
acid, ibuprofen, indomethacin, ketorolac, ketorolac tromethamine,
meclofenamic acid, mefenamic acid, mesalamine, naproxen, niflumic
acid, oxyphenbutazone, pentosan sulfuric polyester, phenylbutazone,
piroxicam, prenazone, salicylates, sodium salicylate,
sulfasalazine, sulindac, suprofen, and tolmetin.
Other antimigraine agents include triptans, ergotamine tartrate,
propanolol hydrochloride, isometheptene mucate, dichloralphenazone,
and others.
Agents administered in the treatment of ADHD include, among others,
methylpenidate, dextroamphetamine, pemoline, imipramine,
desipramine, thioridazine and carbamazepine.
Preferred drugs for sleep disorders include the benzodiazepines,
for instance, alprazolam, chlordiazepoxide, clorazepate
dipotassium, estazolam, medazepam, midazolam, triazolam, as well as
benzodiazepinones, including anthramycin, bromazepam, clonazepam,
devazepide, diazepam, flumazenil, flunitrazepam, flurazepam,
lorasepam, nitrazepam, oxazepam, pirenzepine, prazepam, temazepam,
and triazolam. Another drug is zolpidem (Ambien.RTM., Lorex) which
is currently given as a 5 mg tablet with T.sub.max =1.6 hours; 1/2
Life=2.6 hours (range between 1.4 to 4.5 hours). Peak plasma levels
are reached in about 2 hours with a half-life of about 1.5 to 5.5
hours. Still another drug is triazolam (Halcion.RTM., Pharmacia)
which is a heterocyclic benzodiazepine derivative with a molecular
weight of 343 which is soluble in alcohol but poorly soluble in
water. The usual dose by mouth is 0.125 and 0.25 mg. Temazepam may
be a good candidate for sleep disorders due to a longer duration of
action that is sufficient to maintain sleep throughout the night.
Zaleplon (Sonata.RTM., Wyeth Ayerst) is one drug currently approved
for middle of night sleep restoration due to its short duration of
action.
Other medicaments include analgesics/antipyretics for example,
ketoprofen, flurbiprofen, aspirin, acetaminophen, ibuprofen,
naproxen sodium, buprenorphine hydrochloride, propoxyphene
hydrochloride, propoxyphene napsylate, meperidine hydrochloride,
hydromorphone hydrochloride, morphine sulfate, oxycodone
hydrochloride, codeine phosphate, dihydrocodeine bitartrate,
pentazocine hydrochloride, hydrocodone bitartrate, levorphanol
tartrate, diflunisal, trolamine salicylate, nalbuphine
hydrochloride, mefenamic acid, butorphanol tartrate, choline
salicylate, butalbital, phenyltoloxamine citrate, diphenhydramine
citrate, methotrimeprazine, cinnamedrine hydrochloride,
meprobamate, and others.
Antianxiety medicaments include, for example, lorazepam, buspirone
hydrochloride, prazepam, chlordizepoxide hydrochloride, oxazepam,
clorazepate dipotassium, diazepam, hydroxyzine pamoate, hydroxyzine
hydrochloride, alprazolam, droperidol, halazepam, chlormezanone,
and others.
Examples of antipsychotic agents include haloperidol, loxapine
succinate, loxapine hydrochloride, thioridazine, thioridazine
hydrochloride, thiothixene, fluphenazine hydrochloride,
fluphenazine decanoate, fluphenazine enanthate, trifluoperazine
hydrochloride, chlorpromazine hydrochloride, perphenazine, lithium
citrate, prochlorperazine, and the like.
One example of an antimonic agent is lithium carbonate while
examples of Alzheimer agents include tetra amino acridine,
donapezel, and others.
Sedatives/hypnotics include barbiturates (e.g., pentobarbital,
phenobarbital sodium, secobarbital sodium), benzodiazepines (e.g.,
flurazepam hydrochloride, triazolam, tomazeparm, midazolam
hydrochloride), and others.
Hypoglycemic agents include, for example, ondansetron, granisetron,
meclizine hydrochloride, nabilone, prochlorperazine,
dimenhydrinate, promethazine hydrochloride, thiethylperazine,
scopolamine, and others. Antimotion sickness agents include, for
example, cinnorizine.
Combinations of drugs also can be employed.
In one embodiment of the invention the particles consist of a
medicament, such as, for example, one of the medicaments described
above. In another embodiment, the particles include one or more
additional components. The amount of drug or medicament present in
these particles can range 1.0 to about 90.0 weight percent.
For rescue therapy, particles that include one or more component(s)
which promote(s) the fast release of the medicament into the blood
stream are preferred. As used herein, rapid release of the
medicament into the blood stream refers to release kinetics that
are suitable for providing rescue therapy. In one embodiment,
optimal therapeutic plasma concentration is achieved in less than
10 minutes. It can be achieved in as fast as about 2 minutes and
even less. Optimal therapeutic concentration often can be achieved
in a time frame similar or approaching that observed with
intravenous administration. Generally, optimal therapeutic plasma
concentration is achieved significantly faster than that possible
with oral administration, for example, 2 to 10 times faster.
In a preferred embodiment, the particles include one or more
phospholipids, such as, for example, a phosphatidylcholine,
phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine,
phosphatidylinositol or a combination thereof. In one embodiment,
the phospholipids are endogenous to the lung. Combinations of
phospholipids can also be employed. Specific examples of
phospholipids are shown in Table 1.
TABLE 1 Dilaurylolyphosphatidylcholine (C12;0) DLPC
Dimyristoylphosphatidylcholine (C14;0) DMPC
Dipalmitoylphosphatidylcholine (C16:0) DPPC
Distearoylphosphatidylcholine (18:0) DSPC
Dioleoylphosphatidylcholine (C18:1) DOPC
Dilaurylolylphosphatidylglycerol DLPG
Dimyristoylphosphatidylglycerol DMPG
Dipalmitoylphosphatidylglycerol DPPG Distearoylphosphatidylglycerol
DSPG Dioleoylphosphatidylglycerol DOPG Dimyristoyl phosphatidic
acid DMPA Dimyristoyl phosphatidic acid DMPA Dipalmitoyl
phosphatidic acid DPPA Dipalmitoyl phosphatidic acid DPPA
Dimyristoyl phosphatidylethanolamine DMPE Dipalmitoyl
phosphatidylethanolamine DPPE Dimyristoyl phosphatidylserine DMPS
Dipalmitoyl phosphatidylserine DPPS Dipalmitoyl sphingomyelin DPSP
Distearoyl sphingomyelin DSSP
The phospholipid can be present in the particles in an amount
ranging from about 0 to about 90 weight %. Preferably, it can be
present in the particles in an amount ranging from about 10 to
about 60 weight %.
The phospholipids or combinations thereof can be selected to impart
control release properties to the particles. Particles having
controlled release properties and methods of modulating release of
a biologically active agent are described in U.S. Provisional
Patent Application No. 60/150,742 entitled Modulation of Release
From Dry Powder Formulations by Controlling Matrix Transition,
filed on Aug. 25, 1999, U.S. Non-Provisional patent application
Ser. No. 09/644,736, filed on Aug. 23, 2000, with the title
Modulation of Release From Dry Powder Formulations and U.S.
Non-Provisional patent application Ser. No. 09/792,869 filed on
Feb. 23, 2001, under Attorney Docket No. 2685.1012-004, and with
the title Modulation of Release From Dry Powder Formulations. The
contents of all three applications are incorporated herein by
reference in their entirety. Rapid release, preferred in the
delivery of a rescue therapy medicament, can be obtained for
example, by including in the particles phospholipids characterized
by low transition temperatures. In another embodiment, a
combination of rapid with controlled release particles would allow
a rescue therapy coupled with a more sustained release in a single
cause of therapy. Control release properties can be utilized in
non-rescue, ongoing treatment of a disorder of the CNS.
In another embodiment of the invention the particles can include a
surfactant. As used herein, the term "surfactant" refers to any
agent which preferentially absorbs to an interface between two
immiscible phases, such as the interface between water and an
organic polymer solution, a water/air interface or organic
solvent/air interface. Surfactants generally possess a hydrophilic
moiety and a lipophilic moiety, such that, upon absorbing to
microparticles, they tend to present moieties to the external
environment that do not attract similarly-coated particles, thus
reducing particle agglomeration. Surfactants may also promote
absorption of a therapeutic or diagnostic agent and increase
bioavailability of the agent.
In addition to lung surfactants, such as, for example,
phospholipids discussed above, suitable surfactants include but are
not limited to hexadecanol; fatty alcohols such as polyethylene
glycol (PEG); polyoxyethylene-9-lauryl ether; a surface active
fatty acid, such as palmitic acid or oleic acid; glycocholate;
surfactin; a poloxomer; a sorbitan fatty acid ester such as
sorbitan trioleate (Span 85); and tyloxapol.
The surfactant can be present in the particles in an amount ranging
from about 0 to about 90 weight %. Preferably, it can be present in
the particles in an amount ranging from about 10 to about 60 weight
%.
Methods of preparing and administering particles including
surfactants, and, in particular phospholipids, are disclosed in
U.S. Pat. No 5,855,913, issued on Jan. 5, 1999 to Hanes et al. and
in U.S. Pat. No. 5,985,309, issued on Nov. 16, 1999 to Edwards et
al. The teachings of both are incorporated herein by reference in
their entirety.
In another embodiment of the invention, the particles include an
amino acid. Hydrophobic amino acids are preferred. Suitable amino
acids include naturally occurring and non-naturally occurring
hydrophobic amino acids. Examples of amino acids which can be
employed include, but are not limited to: glycine, proline,
alanine, cysteine, methionine, valine, leucine, tyrosine,
isoleucine, phenylalanine, tryptophan. Preferred hydrophobic amino
acids, include but are not limited to, leucine, isoleucine,
alanine, valine, phenylalanine, glycine and tryptophan. Amino acids
include combinations of hydrophobic amino acids can also be
employed. Non-naturally occurring amino acids include, for example,
beta-amino acids. Both D, L and racemic configurations of
hydrophobic amino acids can be employed. Suitable hydrophobic amino
acids can also include amino acid analogs. As used herein, an amino
acid analog includes the D or L configuration of an amino acid
having the following formula: --NH--CHR--CO--, wherein R is an
aliphatic group, a substituted aliphatic group, a benzyl group, a
substituted benzyl group, an aromatic group or a substituted
aromatic group and wherein R does not correspond to the side chain
of a naturally-occurring amino acid. As used herein, aliphatic
groups include straight chained, branched or cyclic C1-C8
hydrocarbons which are completely saturated, which contain one or
two heteroatoms such as nitrogen, oxygen or sulfur and/or which
contain one or more units of unsaturation. Aromatic groups include
carbocyclic aromatic groups such as phenyl and naphthyl and
heterocyclic aromatic groups such as imidazolyl, indolyl, thienyl,
furanyl, pyridyl, pyranyl, oxazolyl, benzothienyl, benzofuranyl,
quinolinyl, isoquinolinyl and acridintyl.
Suitable substituents on an aliphatic, aromatic or benzyl group
include --OH, halogen (--Br, --Cl, --I and --F) --O(aliphatic,
substituted aliphatic, benzyl, substituted benzyl, aryl or
substituted aryl group), --CN, --NO.sub.2, --COOH, --NH.sub.2,
--NH(aliphatic group, substituted aliphatic, benzyl, substituted
benzyl, aryl or substituted aryl group), --N(aliphatic group,
substituted aliphatic, benzyl, substituted benzyl, aryl or
substituted aryl group).sub.2, --COO(aliphatic group, substituted
aliphatic, benzyl, substituted benzyl, aryl or substituted aryl
group), --CONH.sub.2, --CONH(aliphatic, substituted aliphatic
group, benzyl, substituted benzyl, aryl or substituted aryl
group)), --SH, --S(aliphatic, substituted aliphatic, benzyl,
substituted benzyl, aromatic or substituted aromatic group) and
--NH--C(.dbd.NH)--NH.sub.2. A substituted benzylic or aromatic
group can also have an aliphatic or substituted aliphatic group as
a substituent. A substituted aliphatic group can also have a
benzyl, substituted benzyl, aryl or substituted aryl group as a
substituent. A substituted aliphatic, substituted aromatic or
substituted benzyl group can have one or more substituents.
Modifying an amino acid substituent can increase, for example, the
lypophilicity or hydrophobicity of natural amino acids which are
hydrophillic.
A number of the suitable amino acids, amino acids analogs and salts
thereof can be obtained commercially. Others can be synthesized by
methods known in the art. Synthetic techniques are described, for
example, in Green and Wuts, "Protecting Groups in Organic
Synthesis", John Wiley and Sons, Chapters 5 and 7, 1991.
Hydrophobicity is generally defined with respect to the partition
of an amino acid between a nonpolar solvent and water. Hydrophobic
amino acids are those acids which show a preference for the
nonpolar solvent. Relative hydrophobicity of amino acids can be
expressed on a hydrophobicity scale on which glycine has the value
0.5. On such a scale, amino acids which have a preference for water
have values below 0.5 and those that have a preference for nonpolar
solvents have a value above 0.5. As used herein, the term
hydrophobic amino acid refers to an amino acid that, on the
hydrophobicity scale has a value greater or equal to 0.5, in other
words, has a tendency to partition in the nonpolar acid which is at
least equal to that of glycine.
Combinations of hydrophobic amino acids can also be employed.
Furthermore, combinations of hydrophobic and hydrophilic
(preferentially partitioning in water) amino acids, where the
overall combination is hydrophobic, can also be employed.
Combinations of one or more amino acids and one or more
phospholipids or surfactants can also be employed. Materials which
impart fast release kinetics to the medicament are preferred.
The amino acid can be present in the particles of the invention in
an amount of at least 10 weight %. Preferably, the amino acid can
be present in the particles in an amount ranging from about 20 to
about 80 weight %. The salt of a hydrophobic amino acid can be
present in the particles of the invention in an amount of at least
10% weight. Preferably, the amino acid salt is present in the
particles in an amount ranging from about 20 to about 80 weight %.
Methods of forming and delivering particles which include an amino
acid are described in U.S. patent application Ser. No. 09/382,959,
filed on Aug. 25, 1999, entitled Use of Simple Amino Acids to Form
Porous Particles During Spray Drying and in U.S. Non-Provisional
Patent Application No. 09/644,320, filed on Aug. 23, 2000, titled
Use of Simple Amino Acids to Form Porous Particles, the teachings
of both are incorporated herein by reference in their entirety.
In another embodiment of the invention, the particles include a
carboxylate moiety and a multivalent metal salt. One or more
phospholipids also can be included. Such compositions are described
in U.S. Provisional Application No. 60/150,662, filed on Aug. 25,
1999, entitled Formulation for Spray-Drying Large Porous Particles,
and U.S. Non-Provisional Patent Application No. 09/644,105, filed
on Aug. 23, 2000, titled Formulation for Spray-Drying Large Porous
Particles, the teachings of both are incorporated herein by
reference in their entirety. In a preferred embodiment, the
particles include sodium citrate and calcium chloride.
Other materials, preferably materials which promote fast release
kinetics of the medicament can also be employed. For example,
biocompatible, and preferably biodegradable polymers can be
employed. Particles including such polymeric materials are
described in U.S. Pat. No. 5,874,064, issued on Feb. 23, 1999 to
Edwards et al., the teachings of which are incorporated herein by
reference in their entirety.
The particles can also include a material such as, for example,
dextran, polysaccharides, lactose, trehalose, cyclodextrins,
proteins, peptides, polypeptides, fatty acids, inorganic compounds,
phosphates.
In one specific example, the particles include (by weight percent)
50% L-Dopa, 25% DPPC, 15% sodium citrate and 10% calcium chloride.
In another specific example, the particles include (by weight
percent) 50% L-Dopa, 40% leucine and 10% sucrose. In yet another
embodiment the particles include (by weight percent) 10%
benzodiazepine, 20% sodium citrate, 10% calcium chloride and 60%
DPPC.
In a preferred embodiment, the particles of the invention have a
tap density less than about 0.4 g/cm.sup.3. Particles which have a
tap density of less than about 0.4 g/cm.sup.3 are referred herein
as "aerodynamically light particles". More preferred are particles
having a tap density less than about 0.1 g/cm.sup.3. Tap density
can be measured by using instruments known to those skilled in the
art such as but not limited to the Dual Platform Microprocessor
Controlled Tap Density Tester (Vankel, N.C.) or a GeoPyc.TM.
instrument (Micrometrics Instrument Corp., Norcross, Ga. 30093).
Tap density is a standard measure of the envelope mass density. Tap
density can be determined using the method of USP Bulk Density and
Tapped Density, United States Pharmacopeia convention, Rockville,
Md, 10.sup.th Supplement, 4950-4951, 1999. Features which can
contribute to low tap density include irregular surface texture and
porous structure.
The envelope mass density of an isotropic particle is defined as
the mass of the particle divided by the minimum sphere envelope
volume within which it can be enclosed. In one embodiment of the
invention, the particles have an envelope mass density of less than
about 0.4 g/cm.sup.3.
Aerodynamically light particles have a preferred size, e.g., a
volume median geometric diameter (VMGD) of at least about 5 microns
(.mu.m). In one embodiment, the VMGD is from about 5 .mu.m to about
30 .mu.m. In another embodiment of the invention, the particles
have a VMGD ranging from about 10 .mu.m to about 30 .mu.m. In other
embodiments, the particles have a median diameter, mass median
diameter (MMD), a mass median envelope diameter (MMED) or a mass
median geometric diameter (MMGD) of at least 5 .mu.m, for example
from about 5 .mu.m and about 30 .mu.m.
The diameter of the spray-dried particles, for example, the VMGD,
can be measured using an electrical zone sensing instrument such as
a Multisizer IIe, (Coulter Electronic, Luton, Beds, England), or a
laser diffraction instrument (for example Helos, manufactured by
Sympatec, Princeton, N.J.). Other instruments for measuring
particle diameter are well know in the art. The diameter of
particles in a sample will range depending upon factors such as
particle composition and methods of synthesis. The distribution of
size of particles in a sample can be selected to permit optimal
deposition to targeted sites within the respiratory tract.
Aerodynamically light particles preferably have "mass median
aerodynamic diameter" (MMAD), also referred to herein as
"aerodynamic diameter", between about 1 .mu.m and about 5 .mu.m. In
another embodiment of the invention, the MMAD is between about 1
.mu.m and about 3 .mu.m. In a further embodiment, the MMAD is
between about 3 .mu.m and about 5 .mu.m.
Experimentally, aerodynamic diameter can be determined by employing
a gravitational settling method, whereby the time for an ensemble
of particles to settle a certain distance is used to infer directly
the aerodynamic diameter of the particles. An indirect method for
measuring the mass median aerodynamic diameter (MMAD) is the
multi-stage liquid impinger (MSLI).
The aerodynamic diameter, d.sub.aer, can be calculated from the
equation:
where d.sub.g is the geometric diameter, for example the MMGD, and
.rho. is the powder density.
Particles which have a tap density less than about 0.4 g/cm.sup.3,
median diameters of at least about 5 .mu.m, and an aerodynamic
diameter of between about 1 .mu.m and about 5 .mu.m, preferably
between about 1 .mu.m and about 3 .mu.m, are more capable of
escaping inertial and gravitational deposition in the oropharyngeal
region, and are targeted to the airways, particularly the deep
lung. The use of larger, more porous particles is advantageous
since they are able to aerosolize more efficiently than smaller,
denser aerosol particles such as those currently used for
inhalation therapies.
In comparison to smaller, relatively denser particles the larger
aerodynamically light particles, preferably having a median
diameter of at least about 5 .mu.m, also can potentially more
successfully avoid phagocytic engulfment by alveolar macrophages
and clearance from the lungs, due to size exclusion of the
particles from the phagocytes' cytosolic space. Phagocytosis of
particles by alveolar macrophages diminishes precipitously as
particle diameter increases beyond about 3 .mu.m. Kawaguchi, H., et
al., Biomaterials 7: 61-66 (1986); Krenis, L. J. and Strauss, B.,
Proc. Soc. Exp. Med., 107: 748-750 (1961); and Rudt, S. and Muller,
R. H., J. Contr. Rel., 22: 263-272 (1992). For particles of
statistically isotropic shape, such as spheres with rough surfaces,
the particle envelope volume is approximately equivalent to the
volume of cytosolic space required within a macrophage for complete
particle phagocytosis.
The particles maybe fabricated with the appropriate material,
surface roughness, diameter and tap density for localized delivery
to selected regions of the respiratory tract such as the deep lung
or upper or central airways. For example, higher density or larger
particles may be used for upper airway delivery, or a mixture of
varying sized particles in a sample, provided with the same or
different therapeutic agent may be administered to target different
regions of the lung in one administration. Particles having an
aerodynamic diameter ranging from about 3 to about 5 .mu.m are
preferred for delivery to the central and upper airways. Particles
having and aerodynamic diameter ranging from about 1 to about 3
.mu.m are preferred for delivery to the deep lung.
Inertial impaction and gravitational settling of aerosols are
predominant deposition mechanisms in the airways and acini of the
lungs during normal breathing conditions. Edwards, D. A., J.
Aerosol Sci., 26: 293-317 (1995). The importance of both deposition
mechanisms increases in proportion to the mass of aerosols and not
to particle (or envelope) volume. Since the site of aerosol
deposition in the lungs is determined by the mass of the aerosol
(at least for particles of mean aerodynamic diameter greater than
approximately 1 .mu.m), diminishing the tap density by increasing
particle surface irregularities and particle porosity permits the
delivery of larger particle envelope volumes into the lungs, all
other physical parameters being equal.
The low tap density particles have a small aerodynamic diameter in
comparison to the actual envelope sphere diameter. The aerodynamic
diameter, d.sub.aer, is related to the envelope sphere diameter, d
(Gonda, I., "Physico-chemical principles in aerosol delivery," in
Topics in Pharmaceutical Sciences 1991 (eds. D. J. A. Crommelin and
K. K. Midha), pp.95-117, Stuttgart: Medpharm Scientific Publishers,
1992)), by the formula:
where the envelope mass .rho. is in units of g/cm.sup.3. Maximal
deposition of monodispersed aerosol particles in the alveolar
region of the human lung (.about.60%) occurs for an aerodynamic
diameter of approximately d.sub.aer =3 .mu.m. Heyder, J. et al., J.
Aerosol Sci., 17: 811-825 (1986). Due to their small envelope mass
density, the actual diameter d of aerodynamically light particles
comprising a monodisperse inhaled powder that will exhibit maximum
deep-lung deposition is:
where d is always greater than 3 .mu.m. For example,
aerodynamically light particles that display an envelope mass
density, .rho.=0.1 g/cm.sup.3, will exhibit a maximum deposition
for particles having envelope diameters as large as 9.5 .mu.m. The
increased particle size diminishes interparticle adhesion forces.
Visser, J., Powder Technology, 58: 1-10. Thus, large particle size
increases efficiency of aerosolization to the deep lung for
particles of low envelope mass density, in addition to contributing
to lower phagocytic losses.
The aerodynamic diameter can be calculated to provide for maximum
deposition within the lungs. Previously this was achieved by the
use of very small particles of less than about five microns in
diameter, preferably between about one and about three microns,
which are then subject to phagocytosis. Selection of particles
which have a larger diameter, but which are sufficiently light
(hence the characterization "aerodynamically light"), results in an
equivalent delivery to the lungs, but the larger size particles are
not phagocytosed. Improved delivery can be obtained by using
particles with a rough or uneven surface relative to those with a
smooth surface.
In another embodiment of the invention, the particles have an
envelope mass density, also referred to herein as "mass density" of
less than about 0.4 g/cm.sup.3. Particles also having a mean
diameter of between about 5 .mu.m and about 30 .mu.m are preferred.
Mass density and the relationship between mass density, mean
diameter and aerodynamic diameter are discussed in U.S. application
Ser. No. 08/655,570, filed on May 24, 1996, which is incorporated
herein by reference in its entirety. In a preferred embodiment, the
aerodynamic diameter of particles having a mass density less than
about 0.4 g/cm.sup.3 and a mean diameter of between about 5 .mu.m
and about 30 .mu.m mass mean aerodynamic diameter is between about
1 .mu.m and about 5 .mu.m.
Suitable particles can be fabricated or separated, for example by
filtration or centrifugation, to provide a particle sample with a
preselected size distribution. For example, greater than about 30%,
50%, 70%, or 80% of the particles in a sample can have a diameter
within a selected range of at least about 5 .mu.m. The selected
range within which a certain percentage of the particles must fall
may be for example, between about 5 and about 30 .mu.m, or
optimally between about 5 and about 15 .mu.m. In one preferred
embodiment, at least a portion of the particles have a diameter
between about 9 and about 11 .mu.m. Optionally, the particle sample
also can be fabricated wherein at least about 90%, or optionally
about 95% or about 99%, have a diameter within the selected range.
The presence of the higher proportion of the aerodynamically light,
larger diameter particles in the particle sample enhances the
delivery of therapeutic or diagnostic agents incorporated therein
to the deep lung. Large diameter particles generally mean particles
having a median geometric diameter of at least about 5 .mu.m.
In a preferred embodiment, suitable particles which can be employed
in the method of the invention are fabricated by spray drying. In
one embodiment, the method includes forming a mixture including
L-Dopa or another medicament, or a combination thereof, and a
surfactant, such as, for example, the surfactants described above.
In a preferred embodiment, the mixture includes a phospholipid,
such as, for example the phospholipids described above. The mixture
employed in spray drying can include an organic or aqueous-organic
solvent.
Suitable organic solvents that can be employed include but are not
limited to alcohols for example, ethanol, methanol, propanol,
isopropanol, butanols, and others. Other organic solvents include
but are not limited to perfluorocarbons, dichloromethane,
chloroform, ether, ethyl acetate, methyl tert-butyl ether and
others.
Co-solvents include an aqueous solvent and an organic solvent, such
as, but not limited to, the organic solvents as described above.
Aqueous solvents include water and buffered solutions. In one
embodiment, an ethanol water solvent is preferred with the
ethanol:water ratio ranging from about 50:50 to about 90:10
ethanol:water.
The spray drying mixture can have a neutral, acidic or alkaline pH.
Optionally, a pH buffer can be added to the solvent or co-solvent
or to the formed mixture. Preferably, the pH can range from about 3
to about 10.
Suitable spray-drying techniques are described, for example, by K.
Masters in "Spray Drying Handbook", John Wiley & Sons, New
York, 1984. Generally, during spray-drying, heat from a hot gas
such as heated air or nitrogen is used to evaporate the solvent
from droplets formed by atomizing a continuous liquid feed. Other
spray-drying techniques are well known to those skilled in the art.
In a preferred embodiment, a rotary atomizer is employed. An
example of suitable spray driers using rotary atomization includes
the Mobile Minor spray drier, manufactured by Niro, Denmark. The
hot gas can be, for example, air, nitrogen or argon.
In a specific example, 250 milligrams (mg) of L-Dopa in 700
milliliters (ml) of ethanol are combined with 300 ml of water
containing 500 mg L-Dopa, 150 mg sodium citrate and 100 mg calcium
chloride and the resulting mixture is spray dried. In another
example, 700 ml of water containing 500 mg L-Dopa, 100 sucrose and
400 mg leucine are combined with 300 ml of ethanol and the
resulting mixture is spray dried.
The particles can be fabricated with a rough surface texture to
reduce particle agglomeration and improve flowability of the
powder. The spray-dried particles have improved aerosolization
properties. The spray-dried particle can be fabricated with
features which enhance aerosolization via dry powder inhaler
devices, and lead to lower deposition in the mouth, throat and
inhaler device.
The particles of the invention can be employed in compositions
suitable for drug delivery to the pulmonary system. For example,
such compositions can include the particles and a pharmaceutically
acceptable carrier for administration to a patient, preferably for
administration via inhalation. The particles may be administered
alone or in any appropriate pharmaceutically acceptable carrier,
such as a liquid, for example saline, or a powder, for
administration to the respiratory system. They can be co-delivered
with larger carrier particles, not including a therapeutic agent,
the latter possessing mass median diameters for example in the
range between about 50 .mu.m and about 100 .mu.m.
Aerosol dosage, formulations and delivery systems may be selected
for a particular therapeutic application, as described, for
example, in Gonda, I. "Aerosols for delivery of therapeutic and
diagnostic agents to the respiratory tract," in Critical Reviews in
Therapeutic Drug Carrier Systems, 6: 273-313, 1990; and in Moren,
"Aerosol dosage forms and formulations," in: Aerosols in Medicine.
Principles, Diagnosis and Therapy, Moren, et al., Eds, Esevier,
Amsterdam, 1985.
The method of the invention includes delivering to the pulmonary
system an effective amount of a medicament such as, for example, a
medicament described above. As used herein, the term "effective
amount" means the amount needed to achieve the desired effect or
efficacy. The actual effective amounts of drug can vary according
to the specific drug or combination thereof being utilized, the
particular composition formulated, the mode of administration, and
the age, weight, condition of the patient, and severity of the
episode being treated. In rescue therapy, the effective amount
refers to the amount needed to achieve abatement of symptoms or
cessation of the episode. In the case of a dopamine precursor,
agonist or combination thereof it is an amount which reduces the
Parkinson's symptoms which require rescue therapy. Dosages for a
particular patient are described herein and can be determined by
one of ordinary skill in the art using conventional considerations,
(e.g. by means of an appropriate, conventional pharmacological
protocol). For example, effective amounts of oral L-Dopa range from
about 50 milligrams (mg) to about 500 mg. In many instances, a
common ongoing (oral) L-Dopa treatment schedule is 100 mg eight (8)
times a day. During rescue therapy, effective doses of oral L-Dopa
generally are similar to those administered in the ongoing
treatment.
For being effective during rescue therapy, plasma levels of L-dopa
generally are similar to those targeted during ongoing (non-rescue
therapy) L-Dopa treatment. Effective amounts of L-Dopa generally
result in plasma blood concentrations that range from about 0.5
microgram (.mu.g)/liter(l) to about 2.0 .mu.g/l.
It has been discovered in this invention that pulmonary delivery of
L-Dopa doses, when normalized for body weight, result in at least a
2-fold increase in plasma level as well as in therapeutical
advantages in comparison with oral administration. Significantly
higher plasma levels and therapeutic advantages are possible in
comparison with oral administration. In one example, pulmonary
delivery of L-Dopa results in a plasma level increase ranging from
about 2-fold to about 10-fold when compared to oral administration.
Plasma levels that approach or are similar to those obtained with
intravenous administration can be obtained. Similar findings were
made with other drugs suitable in treating disorders of the CNS,
such as, for example, ketoprofen.
Assuming that bioavailability remains the same as dosage is
increased, the amount of oral drug, e.g. L-Dopa, ketoprofen,
required to achieve plasma levels comparable to those resulting
from pulmonary delivery by the methods of the invention can be
determined at a given point after administration. In a specific
example, the plasma levels 2 minutes after oral and administration
by the methods of the invention, respectively, are 1 .mu.g/ml
L-Dopa and 5 .mu.g/ml L-Dopa. Thus 5 times the oral dose would be
needed to achieve the 5 .mu.g/ml level obtained by administering
the drug using the methods of the invention. In another example,
the L-Dopa plasma levels at 120 minutes after administration are
twice as high with the methods of the invention when compared to
oral administration. Thus twice as much L-Dopa is required after
administration 1 .mu.g/ml following oral administration in
comparison to the amount administered using the methods of the
invention.
To obtain a given drug plasma concentration, at a given time after
administration, less drug is required when the drug is delivered by
the methods of the invention than when it is administered orally.
Generally, at least a two-fold dose reduction can be employed in
the methods of the invention in comparison to the dose used in
conventional oral administration. A much higher dose reduction is
possible. In one embodiment of the invention, a five fold reduction
in dose is employed and reductions as high as about ten fold can be
used in comparison to the oral dose.
At least a two-fold dose reduction also is employed in comparison
to other routes of administration, other than intravenous, such as,
for example, intramuscular, subcutaneous, buccal, nasal,
intra-peritoneal, rectal.
In addition or alternatively to the pharmacokinetic effect, (e.g.,
serum level, dose advantage) described above, the dose advantage
resulting from the pulmonary delivery of a drug, e.g., L-Dopa, used
to treat disorders of the CNS, also can be described in terms of a
pharmacodynamic response. Compared to the oral route, the methods
of the invention avoid inconsistent medicament uptake by
intestines, avoidance of delayed uptake following eating, avoidance
of first pass catabolism of the drug in the circulation and rapid
delivery from lung to brain via aortic artery.
As discussed above, rapid delivery to the medicament's site of
action often is desired. Preferably, the effective amount is
delivered on the "first pass" of the blood to the site of action.
The "first pass" is the first time the blood carries the drug to
and within the target organ from the point at which the drug passes
from the lung to the vascular system. Generally, the medicament is
released in the blood stream and delivered to its site of action
within a time period which is sufficiently short to provide rescue
therapy to the patient being treated. In many cases, the medicament
can reach the central nervous system in less than about 10 minutes,
often as quickly as two minutes and even faster.
Preferably, the patient's symptoms abate within minutes and
generally no later than one hour. In one embodiment of the
invention, the release kinetics of the medicament are substantially
similar to the drug's kinetics achieved via the intravenous route.
In another embodiment of the invention, the T.sub.max of the
medicament in the blood stream ranges from about 1 to about 10
minutes. As used herein, the term T.sub.max means the point at
which levels reach a maximum concentration. In many cases, the
onset of treatment obtained by using the methods of the invention
is at least two times faster than onset of treatment obtained with
oral delivery. Significantly faster treatment onset can be
obtained. In one example, treatment onset is from about 2 to about
10 times faster than that observed with oral administration.
If desired, particles which have fast release kinetics, suitable in
rescue therapy, can be combined with particles having sustained
release, suitable in treating the chronic aspects of a condition.
For example, in the case of Parkinson's disease, particles designed
to provide rescue therapy can be co-administered with particles
having controlled release properties.
The administration of more than one dopamine precursor, agonist or
combination thereof, in particular L-Dopa, carbidopa, apomorphine,
and other drugs can be provided, either simultaneously or
sequentially in time. Carbidopa, for example, is often administered
to ensure that peripheral carboxylase activity is completely shut
down. Intramuscular, subcutaneous, oral and other administration
routes can be employed. In one embodiment, these other agents are
delivered to the pulmonary system. These compounds or compositions
can be administered before, after or at the same time. In a
preferred embodiment, particles that are administered to the
respiratory tract include both L-Dopa and carbidopa. The term
"co-administration" is used herein to mean that the specific
dopamine precursor, agonist or combination thereof and/or other
compositions are administered at times to treat the episodes, as
well as the underlying conditions described herein.
In one embodiment regular chronic (non-rescue) L-Dopa therapy
includes pulmonary delivery of L-Dopa combined with oral carbidopa.
In another embodiment, pulmonary delivery of L-Dopa is provided
during the episode, while chronic treatment can employ conventional
oral administration of L-Dopa/carbidopa.
Preferably, particles administered to the respiratory tract travel
through the upper airways (oropharynx and larynx), the lower
airways which include the trachea followed by bifurcations into the
bronchi and bronchioli and through the terminal bronchioli which in
turn divide into respiratory bronchioli leading then to the
ultimate respiratory zone, the alveoli or the deep lung. In a
preferred embodiment of the invention, most of the mass of
particles deposits in the deep lung or alveoli.
Administration of particles to the respiratory system can be by
means such as known in the art. For example, particles are
delivered from an inhalation device. In a preferred embodiment,
particles are administered via a dry powder inhaler (DPI).
Metered-dose-inhalers (MDI), nebulizers or instillation techniques
also can be employed.
Various suitable devices and methods of inhalation which can be
used to administer particles to a patient's respiratory tract are
known in the art. For example, suitable inhalers are described in
U.S. Pat. No. 4,069,819, issued Aug. 5, 1976 to Valentini, et al.,
U.S. Pat. No. 4,995,385 issued Feb. 26, 1991 to Valentini, et al.,
and U.S. Pat. No. 5,997,848 issued Dec. 7, 1999 to Patton, et al.
Other examples include, but are not limited to, the Spinhaler.RTM.
(Fisons, Loughborough, U.K.), Rotahaler.RTM. (Glaxo-Wellcome,
Research Triangle Technology Park, N.C.), FlowCaps.RTM. (Hovione,
Loures, Portugal), Inhalator.RTM. (Boehringer-Ingelheim, Germany),
and the Aerolizer.RTM. (Novartis, Switzerland), the diskhaler
(Glaxo-Wellcome, RTP, N.C.) and others, such as known to those
skilled in the art. In one embodiment, the inhaler employed is
described in U.S. patent application Ser. No. 09/835,302, entitled
Inhalation Device and Method, by David A. Edwards, et al., filed on
Apr. 16, 2001. The entire contents of this application are
incorporated by reference herein.
The invention further is related to methods for administering to
the pulmonary system a therapeutic dose of the medicament in a
small number of steps, and preferably in a single, breath activated
step. The invention also is related to methods of delivering a
therapeutic dose of a drug to the pulmonary system, in a small
number of breaths, and preferably in one or two single breaths. The
methods includes administering particles from a receptacle having,
holding, containing, storing or enclosing a mass of particles, to a
subject's respiratory tract.
In one embodiment of the invention, delivery to the pulmonary
system of particles is by the methods described in U.S. patent
application Ser. No. 09/878,146, High Efficient Delivery of a Large
Therapeutic Mass Aerosol, application Ser. No. 09/591,307, filed
Jun. 9, 2000, and those described in the Continuation-in-Part of
U.S. application Ser. No. 09/591,307, which is filed concurrently
herewith. The entire contents of both these applications are
incorporated herein by reference. As disclosed therein, particles
are held, contained, stored or enclosed in a receptacle.
Preferably, the receptacle, e.g. capsule or blister, has a volume
of at least about 0.37 cm.sup.3 and can have a design suitable for
use in a dry powder inhaler. Larger receptacles having a volume of
at least about 0.48 cm.sup.3, 0.67 cm.sup.3 or 0.95 cm.sup.3 also
can be employed.
In one example, at least 50% of the mass of the particles stored in
the inhaler receptacle is delivered to a subject's respiratory
system in a single, breath-activated step. In another embodiment,
at least 10 milligrams of the medicament is delivered by
administering, in a single breath, to a subject's respiratory tract
particles enclosed in the receptacle. Amounts as high as 15, 20,
25, 30, 35, 40 and 50 milligrams can be delivered.
In one embodiment, delivery to the pulmonary system of particles in
a single, breath-actuated step is enhanced by employing particles
which are dispersed at relatively low energies, such as, for
example, at energies typically supplied by a subject's inhalation.
Such energies are referred to herein as "low." As used herein, "low
energy administration" refers to administration wherein the energy
applied to disperse and/or inhale the particles is in the range
typically supplied by a subject during inhaling.
The invention also is related to methods for efficiently delivering
powder particles to the pulmonary system. In one embodiment of the
invention, at least about 70% and preferably at least about 80% of
the nominal powder dose is actually delivered. As used herein, the
term "nominal powder dose" is the total amount of powder held in a
receptacle, such as employed in an inhalation device. As used
herein, the term nominal drug dose is the total amount of
medicament contained in the nominal amount of powder. The nominal
powder dose is related to the nominal drug dose by the load percent
of drug in the powder.
In a specific example, dry powder from a dry powder inhaler
receptacle, e.g., capsule, holding 25 mg nominal powder dose having
at 50% L-Dopa load, i.e., 12.5 mg L-Dopa, is administered in a
single breath. Based on a conservative 4-fold dose advantage, the
12.5 mg delivered in one breath are the equivalent of about 50 mg
of L-Dopa required in oral administration. Several such capsules
can be employed to deliver higher doses of L-Dopa. For instance a
size 4 capsule can be used to deliver 50 mg of l-Dopa to the
pulmonary system to replace (considering the same conservative
4-fold dose advantage) a 200 mg oral dose.
Properties of the particles enable delivery to patients with highly
compromised lungs where other particles prove ineffective for those
lacking the capacity to strongly inhale, such as young patients,
old patients, infirm patients, or patients with asthma or other
breathing difficulties. Further, patients suffering from a
combination of ailments may simply lack the ability to sufficiently
inhale. Thus, using the methods and particles for the invention,
even a weak inhalation is sufficient to deliver the desired dose.
This is particularly important when using the particles of the
instant invention as rescue therapy for a patient suffering from
debilitating illness of the central nervous system for example but
not limited to migraine, anxiety, psychosis, depression, bipolar
disorder, obsessive compulsive disorder (OCD), convulsions,
seizures, epilepsy, Alzheimer's, and especially, Parkinson's
disease.
The present invention will be further understood by reference to
the following non-limiting examples.
EXEMPLIFICATIONS
EXAMPLE 1
In vivo tests were performed to compare oral and tracheal
administration of L-Dopa in a rat model. Animals received an IP
injection of the peripheral decarboxylase inhibitor carbidopa
(Sigma, St. Louis, Mo.) (200 mg/kg) one hour prior to
administration of L-Dopa. Under ketamine anesthesia, the animals
were divided into two groups. In the first group of animals (N=4),
L-Dopa (8 mg) was suspended in saline containing 2% methylcellulose
and given via oral gavage. In the second group (N=5) a small
tracheotomy was performed to permit placement of a pipette tip with
a modified 2 mm opening through the trachea and into the lungs. The
pipette tip was pre-loaded with powdered L-Dopa (8 mg) and was
interfaced with an oxygen tank using silicone tubing. Coinciding
with the respiratory cycle of the animal, L-Dopa was pushed into
the lungs using a burst of oxygen (5 liters/minute). Blood samples
(200 .mu.l) were withdrawn from a previously placed femoral cannula
at the following time points: 0 (immediately prior to L-Dopa
administration), 1, 5, 15, 30, 45 and 60 minutes following L-Dopa
administration.
Blood levels of L-Dopa, measured, respectively, by mass
spectrometry or HPLC, following administration via oral gavage or
direct administration into the lungs are shown in FIGS. 1A and 1B.
The increase in blood levels of L-Dopa over time following oral
administration was modest. In contrast, administration into the
lungs produced a robust and rapid rise in L-Dopa levels which
peaked between 1 and 5 minutes post drug administration. L-Dopa
levels in this group decreased between 5 and 15 minutes and
remained stable thereafter. Data are presented as the mean.+-.SEM
ng L-Dopa level/ml blood.
Relationship between blood L-Dopa levels and striatal dopamine
levels following delivery of L-Dopa either orally or directly into
the lungs, as described above, are shown in FIGS. 2A and 2B. FIG.
2A shows blood L-Dopa levels immediately prior to L-Dopa (baseline)
and at 2, 15 and 45 minutes following L-Dopa (N=4-6 per time point
for each group). Once again, the levels following administration
into the lungs show a robust and rapid increase in L-Dopa levels,
relative to the modest increases following oral administration.
FIG. 2B shows dopamine levels in the striatum from the same animals
shown in FIG. 2A. Immediately following withdrawal of the blood
sample, the brains were removed and striatum dissected free. Tissue
levels of dopamine were determined using high performance liquid
chromatography (HPLC). Note that the marked difference in blood
L-Dopa levels seen between the two treatments at two minutes was
followed, later in time, by more modest but significant differences
in striatal levels of dopamine. Blood levels are presented as the
mean.+-.SEM ng L-Dopa levels/ml blood. Striatal levels of dopamine
are presented as the mean.+-.SEM ng dopamine/mg protein.
Blood and striatal levels of .sup.14 C following administration of
.sup.14 C-L-Dopa as generally described above were also determined
and are shown in FIG. 3. A total of 25 .mu.Ci of radiolabeled
L-Dopa was mixed with unlabelled L-Dopa to provide a total drug
concentration of 8 mg/rat. Blood samples were taken at 2, 5 and 15
minutes post drug administration L-Dopa (N=6 per time point for
each group). At 5 or 15 minutes post L-Dopa, the striatum was
removed and both the blood and tissues samples were assayed for
.sup.14 C levels using scintillation. The zero minute plasma values
are deduced from other many studies using radioactive agents.
Once again, a robust and rapid increase in plasma levels was
achieved via the pulmonary route, which was reflected in increased
dopamine activity in the brain at both the 5 minute and 15 minute
time points (relative to oral administration).
Direct comparison of plasma .sup.14 C following administration of
.sup.14 C-L-Dopa via oral gavage, inhalation using a tracheotomy
(as described above) or ventilator (Harvard Apparatus, Inc.,
Holliston, Mass.) is shown in FIG. 4. Corresponding brain .sup.14
C-L-Dopa levels are shown in FIG. 5. All animals were briefly
anesthetized using 1% Isoflurane and immobilized in a harness to
allow blood removal via a previously placed femoral cannula. Blood
samples were removed at 0, 2, 5, and 15 minutes post
administration. For L-Dopa administration using the ventilator, a
24 gauge catheter was placed within the trachea and the L-Dopa (25
.mu.Ci) was administered over a 3-5 second period using a tidal
volume of 1 ml and 100 strokes/minutes. Striatal tissue samples
were processed for determinations of levels of radioactivity using
scintillation counts. Both the plasma and brain levels of .sup.14 C
were comparably elevated using both the conventional tracheotomy
methods and the ventilator.
EXAMPLE 2
Blood, brain and peripheral organ levels of .sup.14 C were
determined following administration of .sup.14 C-Carboplatin via
either IV or pulmonary administration. A total of 100 .mu.Ci of
radiolabeled carboplatin was mixed with unlabelled carboplatin to
provide a total drug concentration of 8 mg/rat. All animals were
anesthetized using ketamine. For IV administration, carboplatin was
administered via a previously placed femoral cannula. For pulmonary
administration, a 24 gauge catheter was placed within the trachea
and the carboplatin was administered using a Harvard ventilator
over a 3-5 second period using a tidal volume of 1 ml and 100
strokes/minutes. Blood samples were taken at 10 minutes post drug
administration (N=6 per time point for each group). Brains were
removed and dissected into various regions including the olfactory,
frontal, and occipital cortices, the hippocampus, striatum, and
cerebellum. Peripheral organs included the kidneys, spleen, heart,
testes, and muscle. All samples were then processed for
determinations of .sup.14 C levels using scintillation.
Results are shown in Table 2, which shows scintillation counts of
.sup.14 C-levels in plasma, brain and peripheral organs following
.sup.14 C-carboplatin (100 .mu.Ci/8 mg) administration, and in
FIGS. 6A-6B and 7A-7B. Absolute plasma levels of .sup.14 C were
higher following IV administration. However, the absolute brain
levels were comparable suggesting that delivery to the brain at
this time point was relatively selective. This point is clearer
when the ratio of brain to blood .sup.14 C levels was calculated.
Following pulmonary delivery, .sup.14 C levels were 2833% higher
than observed following IV administration. Absolute levels of
.sup.14 C in peripheral tissue was also lower following pulmonary
administration (92% lower relative to IV). In contrast to the large
differences in selectivity seen in the brain, the relative
peripheral selectivity (derived from dividing the levels of
radioactivity in peripheral organs by that in the blood) was only
47% higher in the pulmonary group. Interestingly though, the
highest levels of .sup.14 C in peripheral tissue were found in the
heart. Together, these data suggest that the brain and the heart
may represent sites of preferential delivery at time point
immediately following pulmonary drug administration.
TABLE 2 10 Minutes Plasma Levels IV 994.348 Lung (n = 6) (%
Difference) 102.215 -89.72% (n = 6) Absolute Brain Levels IV 29.47
(nCi/gram) Lung 27.29 Relative Brain IV 0.03 Selectivity Lung 0.88
(Brain/Blood) (% Difference) +2833% IV(Br/Bl)/Lung(Br/Bl) Absolute
Tissue IV 0.03 Levels Lung 0.88 (Peripheral Organs) (% Difference)
+2833% *excludes kidney IV(Br/Bl)/Lung(Br/Bl) Relative Peripheral
IV 0.44 Selectivity Lung 0.65 (Peripheral/Blood) (% Difference)
+47.727% *excludes kidney IV(Per/Bl)/Lung(Per/Bl)
EXAMPLE 3
Particles comprising L-Dopa and suitable for inhalation were
produced as follows. 2.00123 g DPPC (Avanti Polar Lipids, Lot
#G160PC-25) was added to 2.80 L of ethanol and stirred to dissolve.
0.0817 g L-Dopa (Spectrum, Lot 0Q0128, Laguna Hills, Calif.),
0.9135 g Sodium Citrate (Dehydrate) (Spectrum Lot NX0195), and
0.5283 g Calcium Chloride (Dehydrate) (Spectrum Lot NT0183) were
added to 1.2 L of water and dissolved. The solutions were combined
by adding the water solution to the ethanol solution and then the
solutions were allowed to stir until the solution was clear. The
weight percent of the formulation was approximately: 20% L-Dopa,
50% DPPC, 20% Sodium Citrate, 10% Calcium Chloride.
The final solution was then spray dried in a Niro dryer (Niro,
Inc., Columbus, Md.) using a rotary atomizer and nitrogen drying
gas following the direction of the manufacturer, using the
following spray conditions: T.sub.inlet =120.degree. C.,
T.sub.outlet =54.degree. C., feed rate=65 m/min, heat nitrogen=38
mm H.sub.2 O, atomizer speed=20,000 rpm (V24 atomizer used).
The resulting particle characteristics were: Mass Median
Aerodynamic Diameter (MMAD)=2.141 .mu.m and Volume Median Geometric
Diameter (VMGD)=10.51 .mu.m.
Under ketamine anesthesia, six rats received pulmonary
administration of the formulation described above (20/50/20/10
L-Dopa/DPPC/Sodium Citrate/Calcium Chloride).
The results are shown in FIG. 8. This FIG. shows blood levels of
L-Dopa following administration via oral gavage or direct
administration into the lungs via insufflation. L-Dopa levels were
measured using both HPLC. Animals received an IP injection of the
peripheral decarboxylase inhibitor carbi-dopa (200 mg/kg) 1 hour
prior to administration of L-Dopa. Under ketamine anesthesia, the
animals were divided into 2 groups. In the first group, animals
were fasted overnight and L-Dopa (8 mg) was suspended in saline
containing 1% methylcellulose and given via oral gavage. In the
second group, insufflation was used to deliver the L-Dopa
formulation directly into the lungs. Blood samples (200 .mu.l) were
withdrawn from a previously placed femoral cannula at the following
time points: 0 (immediately prior to L-Dopa administration), 2, 5,
15, and 30 minutes following L-Dopa administration. The increase in
blood levels of L-Dopa over time following oral administration was
modest. In contrast, administration into the lungs produced a
robust and rapid rise in L-Dopa levels. L-Dopa levels in this group
remained elevated relative to oral delivery at 30 minutes post drug
administration. Data were normalized to a dose of 8 mg/kg (the
total oral gavage dose). Data are presented as the mean (.+-.SEM)
ng L-Dopa/ml blood.
EXAMPLE 4
Ketoprofen/DPPC/maltodextrin particles were prepared and
administered in vivo.
Ketoprofen (99.5%) was obtained from Sigma, (St. Louis, Mo.),
dipalmitoyl phosphatidyl choline (DPPC) from Avanti Polar Lipids,
(Alabaster, Ala.) and maltodextrin,M100 (Grain Processing Corp.,
Muscatine, Iowa).
To prepare ketoprofen/DPPC/Maltodextrin solutions, maltodextrin
(0.598 g) was added to 0.60 L USP water. DPPC (0.901 g) was added
to 1.40 L ethanol and stirred until dissolved. The water and
ethanol solutions were combined, resulting in a cloudy solution.
500 ml of this stock solution was used for each run. The addition
of ketoprofen to the DPPC/Maltodextrin stock solution is described
in Table 3.
A Niro Atomizer Portable Spray Dryer (Niro, Inc., Columbus, Md.)
was used to produce the dry powders. Compressed air with variable
pressure (1 to 5 bar) ran a rotary atomizer (2,000 to 30,000 rpm)
located above the dryer. Liquid feed of the
ketoprofen/DPPC/Maltodextrin solutions, with varying rate (20 to 66
ml/min), was pumped continuously by an electronic metering pump
(LMI, model #A151-192s) to the atomizer. Both the inlet and outlet
temperatures were measured. The inlet temperature was controlled
manually; it could be varied between 100.degree. C. and 400.degree.
C., with a limit of control of 5.degree. C. The outlet temperature
was determined by the inlet temperature and such factors as the gas
and liquid feed rates; it varied between 50.degree. C. and
130.degree. C. A container was tightly attached to the 6" cyclone
for collecting the powder product. The spraying conditions for each
solution is given in Table 4, which shows that the spraying
conditions were held nearly constant throughout the study. The
total recovery and yield for each solution is given in Table 5.
The particles were characterized using the Aerosizer (TSI, Inc.,
Amherst, Mass.) and the RODOS dry powder disperser (Sympatec Inc.,
Princeton, N.J.) as instructed by the manufacturer. For the RODOS,
the geometric diameter was measured at 2 bars. The material from
run #5 was also characterized using a gravimetric collapsed
Andersen Cascade Inpactor (ACI, 2 stage, Anderson Inst., Sunyra,
Ga.). The samples were examined using a scanning electron
microscope (SEM).
Table 5 indicates that increasing the weight % of ketoprofen led to
a decrease in yield. The addition of ketoprofen to the stock
solution linearly decreased yield. This may be due to a decrease in
melting temperature for DPPC when mixed with ketoprofen, leading to
the yield loss.
Table 6 shows that the particles ranged in diameter from 8.8 .mu.m
to 10.2 .mu.m (VMGD) and from 2.65 .mu.m to 3.11 .mu.m (MMAD). The
lowest MMAD particles were for the 8.4% loading material (run
#5).
Table 7 shows the results of a Andersen Collapsed Impactor study
(ACI, gravimetric, n=2) of the material from run #5, the 8.4%
loading material. The fine particle fractions (FPF) below 5.6 .mu.m
and below 3.4 .mu.m are consistent with powders expected to be
respirable.
TABLE 3 Sample Ketoprofen Total solids ID added (mg) (g/L) %
Ketoprofen Run #1 0 1.000 0 Run #2 8.0 1.016 1.6 Run #3 15.1 1.030
3.0 Run #4 30.1 1.060 5.7 Run #5 46.0 1.092 8.4 Run #6 63.0 1.126
11.2
TABLE 4 Temperature Liquid Gas Rotor Inlet Sample (.degree. C.)
Feed Pressure Speed Dew- ID Inlet Outlet (ml/min) (mm H.sub.2 O)
(RPM) point (.degree. C.) Run #1 115 36 75 40 18,600 -27.0 Run #2
113 38 85 40 18,400 -26.8 Run #3 110 38 85 39 18,300 -26.4 Run #4
110 39 85 38 18,400 -25.9 Run #5 110 38 86 39 18,400 -25.4 Run #6
110 38 85 38 18,400 -25.0
TABLE 5 Sample Weight Collected Theoretical Yield Actual Yield ID
(mg) (mg) (% Theoretical) Run #1 186 500 37.2 Run #2 195 508 38.4
Run #3 147 515 28.5 Run #4 127 530 24.0 Run #5 89 546 16.3 Run #6
67 563 11.9
TABLE 6 MGVD (.mu.m, 2 Sample ID MMAD (.mu.m) Std Dev bar) Run #1
3.11 1.48 9.0 Run #2 3.01 1.37 9.3 Run #3 2.83 1.40 10.3 Run #4
2.84 1.41 10.4 Run #5 2.65 1.39 9.8 Run #6 2.83 1.38 8.8
TABLE 7 Stage 0 1.33 mg Stage 2 2.75 mg Stage F 3.17 mg Capsule
Fill 12.37 mg Weight < 5.6 .mu.m 5.92 FPF.sub.5.6 0.479 Weight
< 3.4 .mu.m 3.17 FPF.sub.3.4 0.256
350 mg of particles containing 8% ketoprofen in 60/40
DPPC/maltodextrin were produced as described above and administered
to 20 Sprague Dawley rats. Each of 8 rats were given 7 mg of powder
via insufflation, and each of 7 rats were orally given 7 mg of
powder dissolved in 50% ethanol. Time points were set at 0, 5, 15,
30, 60, 120, 240, 360 and 480 minutes. For t=0, 4 animals were
tested without dosing. For each time point after, samples were
taken from either 3 or 4 rats. Each rat was used for 4 time points,
with 3 or 4 animals each in four groups. The animals were
distributed as follows: 3 animals oral at 5, 30, 120, 360 minutes;
4 animals insufflation at 15, 60, 240, 480 minutes. Sufficient
blood was drawn at each time point for the ketoprofen plasma assay.
Blood samples were centrifuged, the plasma collected and then
frozen at -20.degree. C. prior to shipment to the contract
laboratory for analysis. The assay used in this study has a lower
detection limit of 1.0 mg/ml.
Rats were dosed with ketoprofen via either oral or pulmonary
administration to determine if the pulmonary route would alter the
time required to achieve maximum plasma concentration. The results
(FIGS. 9-11) show that the pulmonary delivery route leads to a very
rapid uptake with C.sub.max occurring at .ltoreq.10 minutes. The
rats that received oral doses of ketoprofen displayed somewhat
anomalous pharmacokinetic behavior, with the relative
bioavailability being about half of that displayed for rats dosed
via the pulmonary route. This result was unexpected as ketoprofen
is 90% orally bioavailable in the human model. This anomaly for the
orally dosed rats does not, however, invalidate the significance of
the early C.sub.max seen for the rats dosed via the pulmonary
route.
The results are provided in Table 8. The averages were calculated
along with the standard errors and p values. The results are also
presented graphically in FIGS. 9-11, wherein FIG. 9 shows both data
sets, FIG. 10 gives the oral dosing results and FIG. 11 shows the
insufflation results. For FIG. 9, points with p<0.05 are marked
with "*" and points with p<0.01 are marked with "**". For FIGS.
10 and 11, AUC (area under the curve) was performed via numerical
integration of the curve with smooth interpolation.
At t=0, all rats showed ketoprofen levels below the detection limit
for the assay. From t=5 min to t=60 min, the insufflated rats had
significantly higher plasma levels of ketoprofen. At t=120 min and
t=240 min, the plasma levels of ketoprofen of the two groups were
statistically equivalent. At t=360 min and t=480, the plasma levels
of ketoprofen for both groups approached the detection limit for
the assay.
The ratio of the AUCs for insulflated rats vs. orally dosed was
about 2. The plasma concentrations for ketoprofen at the early time
points were statistically significant as well.
C.sub.max for the insufflated rats clearly occurred at <15 min
and C.sub.max for the orally dosed rats occurred between 15-60 min.
Due to the large standard error and the relatively low plasma
levels for this group, it is not possible to accurately determine
the time required for Cmax.
Pulmonary administration resulted in Cmax occurring very quickly
(<15 min) compared to oral dosing (t=15 to 60 min).
The insufflated rats showed higher bioavailability compared to the
orally dosed rats. This is unexpected as previous studies have
shown ketoprofen to have consistently high (>90%)
bioavailability in humans when dosed orally, subcutaneously or
rectally. Since the pharmokinetic behavior of ketoprofen delivered
orally is well-known, the anomalous results seen here for the
orally dosed group do not invalidate the results seen for the
insufflation group.
TABLE 8 Oral Dosing Dosing Group Pulmonary Group Time Avg. St. Avg.
Std. P Min. (ug/ml) Dev. (ug/ml) Dev. Value 0 1.0 N/A 1.0 N/A 5 1.7
0.75 9.6 1.27 0.0003 15 2.1 0.76 7.6 0.28 0.0000 30 1.9 0.12 5.5
0.76 0.0012 60 2.0 0.13 4.5 0.60 0.0002 120 1.7 0.31 2.4 0.44
0.0929 240 1.4 0.05 1.8 0.63 0.2554 360 1.0 0.06 1.8 0.35 0.0224
480 1.0 0.00 1.3 0.47 0.2174 Average plasma levels of Ketoprofen
from oral and pulmonary group
EXAMPLE 5
The following experimental methods and instrumentation were
employed to determine the physical characteristics of particles
including L-DOPA and suitable for pulmonary delivery.
Aerodynamic diameter was analyzed using the API AeroDisperser and
Aerosizer (TSI, Inc., St. Paul, Minn.) following standard
procedures (Alkermes SOP# MS-034-005). Sample powder was introduced
and dispersed in the AeroDisperser and then accelerated through a
nozzle in the Aerosizer. A direct time-of-flight measurement was
made for each particle in the Aerosizer, which was dependent on the
particle's inertia. The time-of-flight distribution was then
translated into a mass-based aerodynamic particle size distribution
using a force balance based on Stokes law.
Geometric diameter was determined using a laser diffraction
technique (Alkermes SOP# MS-021-005). The equipment consists of a
HELOS diffractometer and a RODOS disperser (Sympatec, Inc.,
Princeton, N.J.). The RODOS disperser applies a shear force to a
sample of particles, controlled by the regulator pressure of the
incoming compressed air. The dispersed particles travel through a
laser beam where the resulting diffracted light pattern produced is
collected by a series of detectors. The ensemble diffraction
pattern is then translated into a volume-based particle size
distribution using the Fraunhofer diffraction model, on the basis
that smaller particles diffract light at larger angles.
The aerodynamic properties of the powders dispersed from the
inhaler device were assessed with a 2-stage MkII Anderson Cascade
Impactor (Anderson Instruments, Inc., Smyrna, Ga.). The instrument
consists of two stages that separate aerosol particles based on
aerodynamic diameter. At each stage, the aerosol stream passes
through a set of nozzles and impinges on the corresponding
impaction plate. Particles having small enough inertia will
continue with the aerosol stream to the next stage, while the
remaining particles will impact upon the plate. At each successive
stage, the aerosol passes through nozzles at a higher velocity and
aerodynamically smaller particles are collected on the plate. After
the aerosol passes through the final stage, a filter collects the
smallest particles that remain.
Prior to determining the loading of drug within a dry powder, the
drug had to be first be separated from the excipients within the
powder. An extraction technique to separate L-Dopa from the
excipient DPPC was developed. Particles were first dissolved in 50%
chloroform/50% methanol. The insoluble L-Dopa was pelleted out and
washed with the same solvent system and then solubilized in 0.5 M
hydrochloric acid. DPPC was spiked with L-DOPA to determine
recovery. Samples were injected onto a reverse phase high pressure
liquid chromatography (HPLC) for analysis.
Separation was achieved using a Waters Symmetry C18 5-.mu.m column
(150-mm.times.4.6-mm ID). The column was kept at 30.degree. C. and
samples were kept at 25.degree. C. Injection volume was 10 .mu.L.
The mobile phase was prepared from 2.5% methanol and 97.5% aqueous
solution (10.5 g/L citric acid, 20 mg/L EDTA, 20 mg/L
1-octanesulfonic acid sodium salt monohydrate). Mobile phase was
continually stirred on a stir plate and degassed through a Waters
in-line degassing system. L-Dopa was eluted under isocratic
conditions. Detection was performed using an ultraviolet detector
set at wavelength 254 nm.
Since the average single oral dose of L-Dopa generally ranges from
100-150 mg, experiments were conducted to prepare particles
suitable for inhalation which included high loads of L-Dopa.
Formulations of 20% and 40% L-Dopa load were studied. Carbidopa, a
decarboxylase inhibitor given in conjunction with L-Dopa to prevent
peripheral decarboxylation, was also included at a 4:1
weight/weight (w/w) ratio in some of the formulations. L-Dopa and
combination of L-Dopa and carbidopa were successfully sprayed with
DPPC formulations. The optimal formulation consisted of L-Dopa
and/or carbidopa, 20% (w/w) sodium citrate, and 10% (w/w) calcium
chloride, and the remainder dipalmitoyl phosphatidyl chlorine
(DPPC).
Details on formulations and the physical properties of the
particles obtained are summarized in Table 9. The aerodynamic size
or the mass median aerodynamic diameter (MMAD) was measured with an
Aerosizer, and the geometric size or the volume median geometric
diameter (VMGD) was determined by laser diffraction, and the fine
particle fraction (FPF) was measured using a 2-stage Andersen
Cascade Impactor. As shown in FIG. 12 and by the VMGD ratios in
Table 9, the powders were flow rate independent. Scanning electron
micrography was employed to observe the particles.
TABLE 9 L-Dopa/Carbi dopa VMGD Load (%) VMGD (.mu.m) at ratio MMAD
FPF (%) ID Yield (%) 2 bar 0.5/4.0 bar (.mu.m) 5.6/3.4 20/0 >40
9.9 NA 2.7 NA 40/0 >40 8.0 1.2 3.3 42/17 20/5 42 10 1.6 3.1
64/38 40/10 >20 7.4 1.6 3.8 40/14
L-Dopa integrity appeared to be preserved through the formulation
and spray drying process. L-Dopa was extracted from L-Dopa powders
and analyzed by reverse phase HPLC. No impurities were detected in
the L-Dopa powders (FIG. 13A); the early peaks eluted around 1-2
minutes are due to solvent as can be seen from FIG. 13B which is a
blank sample that did not contain L-Dopa. The purity of L-Dopa
recovered from the particles was 99.8% and 99.9% respectively for
the 20% and 40% loaded particles.
To determine the loading (weight percent) of L-Dopa within the
powder, the L-Dopa was first separated from the excipients in the
formulation and then analyzed by reverse phase HPLC. Results of the
L-Dopa recovery from the powders and the final load calculations
are given in Table 10. Both extraction recoveries and load
determination were satisfactory. The determined actual weight
percent of L-Dopa in the powder was approximately 87% of the
theoretical drug load.
TABLE 10 Powder Formulation Extraction recovery % Actual load (%)
20/0 100 .+-. 4.5 17.3 .+-. 0.2 40/0 101 .+-. 2.8 35.0 .+-. 5.4
EXAMPLE 6
Determinations of plasma levels of L-Dopa were made following IV
injection, oral gavage, or insufflation into the lungs. Carbidopa
generally is administered to ensure that peripheral decarboxylase
activity is completely shut down. In this example, animals received
an intraperitoneal (IP) injection of the peripheral decarboxylase
inhibitor carbidopa (200 mg/kg) 1 hour prior to administration of
L-Dopa. Under ketamine anesthesia, the animals were divided into 3
groups. In the first group of animals, L-Dopa (2 mg) was suspended
in saline containing 1% methylcellulose and 1% ascorbic acid and
given via oral gavage. In the second group, an insufflation
technique was used for pulmonary administration of particles
including L-Dopa (20% loading density). A laryngoscope was used to
visualize the rat's epiglottis and the blunt-tip insufflation
device (PennCentury Insufflation powder delivery device) was
inserted into the airway. A bolus of air (3 cc), from an attached
syringe, was used to delivery the pre-loaded powder from the
chamber of the device into the animal's lungs. A total of 10 mg of
powder (2 mg L-Dopa) was delivered. In the third group, a
previously-placed femoral cannula was used to delivery a bolus (2-3
second) of L-Dopa (2 mg). Blood samples (200 .mu.L) were withdrawn
from each animal using the femoral cannula at the following
timepoints: 0 (immediately prior to L-Dopa administration), 2, 5,
15, 30, 60, 120, and 240 minutes following L-Dopa administration.
All samples were processed for L-Dopa determinations using
HPLC.
The results of a pharmacokinetic study using the procedure
described are shown in FIGS. 14A and 14B. The results of a
comparison of pulmonary delivery of L-Dopa with oral administration
are depicted in FIG. 14A. Following insufflation, peak plasma
levels of L-Dopa were seen at the earliest time point measured (2
minutes) and began to decrease within 15 minutes of administration
while still remaining elevated, relative to oral administration,
for up to 120 minutes. In contrast, oral administration of L-Dopa
resulted in a more gradual increase in plasma L-Dopa levels, which
peaked at 15-30 minutes following administration and then decreased
gradually over the next 1-2 hours.
Intravenous, oral and pulmonary delivery also were compared. The
results are shown in FIG. 14B. This panel depicts the same data
presented in FIG. 14A with the addition of the IV administration
group which allows direct comparisons of the plasma L-Dopa levels
obtained following all three routes of administration (pulmonary,
oral, and IV). Data are presented as the mean.+-.SEM .mu.g
L-Dopa/mL blood. Plasma levels of L-Dopa rapidly increased
following intravenous (IV) administration. The highest levels of
L-Dopa were seen at 2 minutes and decreased rapidly thereafter.
Bioavailability was estimated by performing area under the curve
(AUC) calculations. Over the entire time course of the study (0-240
min), the relative bioavailability (compared to IV) of pulmonary
L-Dopa was approximately 75% as compared 33% for oral L-Dopa. The
relative bioavailability of pulmonary L-Dopa at 15 min and 60 min
post administration was 38% and 62%, respectively, while that of
oral L-Dopa was 9% and 24%, respectively.
EXAMPLE 7
Pharmacodynamic evaluation of rats receiving L-Dopa also was
undertaken. Rats received unilateral injections of the neurotoxin
6-OHDA (specific for dopamine neurons in the brain) into the medial
forebrain bundle. Rats were then screened to assure successful
striatal dopamine depletion using a standard apomorphine-induced
turning paradigm. Beginning two weeks after surgery, animals were
tested weekly for three weeks for apomorphine-induced rotation
behavior. For this test, animals received an IP injection of
apomorphine (0.25 mg/kg for the first test and 0.1 mg/kg for the
following two tests) and were placed into a cylindrical Plexiglass
bucket. Each 360-degree rotation was counted for 30 minutes and
only those animals exhibiting >200 rotations/30 minutes (12/30
lesioned rats) were used in behavioral testing.
The lesioned rats were challenged with several motor tasks post
L-Dopa administration. The data from the studies (placing task,
bracing task, akinesia) further emphasized the advantage of
pulmonary delivery over oral delivery.
In one test, animals passing the apomorphine challenge were tested
using a "placing task". Prior to each test day, animals received an
IP injection of the peripheral decarboxylase inhibitor carbidopa
(200 mg/kg). Animals then received oral L-Dopa (0, 20 or 30 mg/kg)
or pulmonary L-Dopa (0, 0.5, 1.0 or 2.0 mg of L-Dopa) and were
tested 15, 30 60 and 120 minutes later. Throughout testing with
oral and pulmonary delivery of L-Dopa, each animal received every
possible drug combination in a randomized fashion.
The pharmacodynamics "placing task" required the animals to make a
directed forelimb movement in response to sensory stimuli. Rats
were held so that their limbs were hanging unsupported. They were
then raised to the side of a table so that their bodies were
parallel to the edge of the table. Each rat received 10 consecutive
trials with each forelimb and the total number of times the rat
placed its forelimb on the top of the table was recorded.
Results from a "placing task" tests are shown in FIGS. 15A and 15B.
At baseline (t=0; immediately prior to L-Dopa administration), the
animals performed nearly perfectly on this task with the unaffected
limb, making greater than 9/10 correct responses. In contrast, the
animals were markedly impaired in their ability to perform the same
task with the impaired limb, making approximately 1 correct
response over the 10 trials.
Oral L-Dopa (FIG. 15A) produced a dose-related improvement in
performance with the impaired limb. At the highest dose tested (30
mg/kg), performance was improved, relative to saline control,
within 30 minutes and peaked between 1-2 hours after drug
administration. The lower dose (20 mg/kg) also improved performance
slightly with maximal effects at 60 minutes and stable performance
thereafter. No changes were noted following administration of the
saline control.
In contrast to oral administration, performance on the "placing
task" rapidly improved following pulmonary delivery of L-Dopa, as
seen in FIG. 15B. At the highest dose tested, significant
improvements occurred within 10 minutes, with peak benefits
observed within 15-30 minutes (as opposed to 1-2 hours with oral
administration). These effects were dose-related, with significant
improvements seen with doses as low as 0.5 mg of L-Dopa. In
comparison to the recovery shown with oral delivery, the behavioral
improvements were seen with markedly lower total doses using the
pulmonary route. For instance, the extent of recovery with 30 mg/kg
of L-Dopa given orally was comparable to the recovery seen with 1
mg of L-Dopa given by the pulmonary route (note that 1 mg of
pulmonary L-Dopa is equivalent to approximately 3 mg/kg, given that
the animals body weight was approximately 300 g). Accordingly, when
the L-Dopa doses were normalized by body weight, this represented
nearly a 10-fold difference in the drug required to produce
equivalent efficacy. Finally, the persistence of the behavioral
improvements was comparable using the two delivery routes.
Results from a bracing test are shown in FIGS. 16A and 16B. This
test was performed using the same animals and at the same time as
the "placing task" test described above. Rats were placed on a
smooth stainless steel surface and gently pushed laterally 90 cm at
approximately 20 cm/second. The number of steps the rat took with
the forelimb on the side in which the rat was moving was recorded.
Each trial included moving the rat 2 times in each direction.
The animals demonstrated a profound impairment in their ability to
perform this task with the impaired limb, making approximately 3
responses compared to approximately 7 with the unaffected limb, as
seen in FIG. 16A. Again, oral administration improved performance
on this task in a dose-related manner. Administration of 30 mg/kg
(approximately 10 mg L-Dopa) improved performance within 30
minutes. Maximal effects were seen within 60 minutes and remained
stable thereafter. A lower dose of oral L-Dopa (20 mg/kg or
approximately 7 mg of L-Dopa) slightly improved performance. Again,
administration of the saline control did not affect
performance.
In contrast to oral administration, performance on this task
rapidly improved following pulmonary administration of L-Dopa, as
shown in FIG. 16B. Significant improvements were seen within 10
minutes, with peak benefits observed within 15-30 minutes (as
opposed to 30-60 minutes with oral administration). These effects
were dose-related, with modest, but statistically significant
improvements seen with as low as 0.5 mg (equivalent to
approximately 1.5 mg/kg). As with the other functional tests, the
behavioral improvement achieved following pulmonary L-Dopa occurs
at doses far below those required to achieve a similar magnitude of
effect following oral delivery. Finally, the persistence of the
behavioral improvements was comparable using the two delivery
routes.
A functional akinesia pharmacodynamics study also was conducted.
The results are shown in FIGS. 17A and 17B. This test was performed
using the same animals and at the same time as the two preceding
tests. In this task, the animal was held so that it was standing on
one forelimb and allowed to move on its own. The number of steps
taken with the forelimb the rat was standing on was recorded during
a 30 second trial for each forelimb.
As was seen with the placing and bracing tests, the animals
demonstrated a profound impairment in their ability to perform the
akinesia task with the impaired limb. While the animals made
approximately 17 steps with the normal limb, they made fewer than
half this number with the impaired limb (range=0-10 steps). Oral
administration (FIG. 17A) improved performance on this task in a
dose-related manner. Administration of 30 mg/kg (approximately 10
mg L-Dopa) improved performance within 30 minutes and maximal
effects were seen within 60 minutes. A lower dose of oral L-Dopa
(20 mg/kg or approximately 6.8 mg of L-Dopa) produced the same
pattern of recovery although the absolute magnitude of improvement
was slightly lower than that seen with the higher dose of L-Dopa.
Performance remained stable between 60 and 120 minutes following
administration of both doses. Administration of the saline control
did not affect performance.
In contrast to oral administration, performance on this task
rapidly improved following pulmonary administration of L-Dopa, as
depicted in FIG. 17B. Significant improvements were seen within 10
minutes, with peak benefits observed within 15-30 minutes (as
opposed to 60 minutes with oral administration). These effects were
dose-related statistically significant (p<0.05) improvements
seen with as low as 1.0 mg. As with the other functional tests, the
behavioral improvement achieved following pulmonary L-Dopa occurred
at doses far below those required to achieve a similar magnitude of
effect following oral delivery. Finally, the persistence of the
behavioral improvements was comparable using the two delivery
routes.
Animals also were tested on a standard pharmacodynamics rotation
test known to be a sensitive and reliable measure of dopamine
activity in the brain. For this test, animals received either oral
L-Dopa (30 mg/kg or approximately 10 mg total) or pulmonary L-Dopa
(2 mg total). These doses were chosen for this test because they
represent the doses of L-Dopa shown to produce maximal efficacy in
the previous functional tests. Following dosing, animals were
placed into a cylindrical Plexiglas bucket. Each 360-degree
rotation was counted and grouped into 5 minute bins over a 120
minute test period. Animals were also tested for rotation behavior
with and without pre-treatment with carbidopa.
All of the animals used in these studies received unilateral
injections of 6-OHDA. Because the dopamine depletions are
unilateral, the uninjected side remained intact and still able
respond to changes in dopamine activity. When these animals were
injected with a dopamine agonist (i.e. L-Dopa) brain dopamine
activity was stimulated preferentially on the intact side. This
resulted in an asymmetrical stimulation of motor activity that was
manifested as a turning or rotational behavior. The onset and
number of rotations provided a measure of both the time course as
well as the extent of increased dopamine activity.
The results are shown in FIG. 18. Oral administration of L-Dopa
produced a marked clockwise rotation behavior that was modest
during the first 10-15 minutes post L-Dopa administration (<5
rotations/animal). During the next 20 minutes, the number of
rotations increased markedly, with peak levels occurring
approximately 30 minutes after L-Dopa indicating increased dopamine
activity in the intact striatum of the brain. During the next 90
minutes, the number of rotations gradually decreased, but this
decrease, relative to peak levels, did not reach statistical
significance (p>0.05).
In contrast to oral administration, pulmonary delivery of L-Dopa
rapidly increased rotation behavior indicating much more rapid
conversion of L-Dopa to dopamine in the intact striatum. Rotations
in this group were greater than 3 times that produced by oral
delivery within the first 10-15 minutes. The numbers of rotations
increased slightly, peaked at 25-30 minutes, and remained
relatively stable thereafter. While a trend towards increased
rotations, relative to oral delivery, was seen 120 minutes after
dosing, this did not reach statistical significance (p >0.05).
Rotation behavior was virtually eliminated in animals that did not
receive pre-treatment with carbidopa (data not shown).
EXAMPLE 8
The pharmacodynamic effects of a pulmonary versus oral
benzodiazepine-type drug, alprazolam, were evaluated using a
standard pre-clinical test of anxiolytic drug action. In this test,
the chemical convulsant pentylenetetrazol (PZT), which is known to
produce well characterized seizures in rodents, was administered to
rats. The test was selected based on its sensitivity to a wide
range of benzodiazapines and to the fact that the relative potency
of benzodiazapines in blocking PZT-induced seizures is believed to
be similar to the magnitude of their anti-anxiety effects in
humans. The ability of alprazolam to block PZT-induced seizures was
used as a measure of the pharmacodynamic effects of alprazolm.
Determinations of the anti-anxiolytic activity of alprazolam were
made following oral gavage, or insufflation directly into the lungs
of rats. Alprazolam (Sigma, St. Louis, Mo. was administered via
aerodynamically light particles which included 10% alprazolam, 20%
sodium citrate, 10% calcium chloride and 60% DPPC. For oral
delivery, alprazolam was suspended in light corn syrup and
administered via gavage. For pulmonary delivery, an insufflation
technique was used. Animals were briefly anesthetized with
isoflurane (1-2%) and a laryngoscope was used to visualize the
epiglottis and the blunt-tip insufflation device (PennCentury
Insufflation powder delivery device) was inserted into the airway.
A bolus of air (3 cc), from an attached syringe, was used to
deliver the pre-loaded powder from the chamber of the device into
the animals' lungs. The doses for pulmonary delivery were 0 (blank
particles that included 20% sodium citrate, 10% calcium chloride
and 70% DPPC), 0.088, 0.175, or 0.35 mgs total alprazolam, and the
doses for oral delivery were 0, 0.088, 0.175, 0.35, 0.70, 1.75, or
3.50 mgs total alprazolam. These doses were chosen to encompass the
range of effective and ineffective oral doses. Accordingly, any
potential benefits of pulmonary delivery could be directly compared
to the oral dose response curve for alprazolam.
For both oral and pulmonary delivery, alprazolam was administered
either 10 or 30 minutes prior to PZT, obtained from Sigma, St.
Louis, Mo., (60 mg/kg given i.p). To control for potential
interactions between alprazolam and isoflurane, all animals
receiving oral alprazolam also received isoflurane immediately
following dosing as described above. For all animals, the number of
seizures as well as the time to seizure onset and seizure duration
was recorded for 45 minutes after administration of PZT. Any animal
that did not exhibit seizure activity was assigned the maximum
possible time for seizure onset (45 minutes) and the minimal
possible time for seizure duration (0 seconds).
Pulmonary delivery of alprazolam produced a rapid and robust
decrease in the incidence of seizures, as shown in Table 11. While
80% of control animals (blank particles) exhibited seizures,
pulmonary alprazolam produced a robust and dose-related decrease in
the number of animals manifesting seizures when administered 10
minutes prior to PZT. With alprazolam doses as low as 0.088 mgs,
only 33% of the animals had seizures. With further dose escalation
to 0.35 mgs of alprazolam, seizure activity was virtually
eliminated with only 13% of the animals exhibiting seizures.
In contrast to the rapid and robust effects of pulmonary
alprazolam, the effects of oral delivery were delayed (Table 11).
When given 30 minutes prior to PZT, oral alprazolam produced a
dose-related decrease in seizures. While only 27% of the animals
had seizures following the highest dose tested (0.35 mgs), this
same dose of alprazolam was ineffective when administered only 10
minutes prior to PZT (i.e, a dose that was maximally effective when
administered by the pulmonary route). These studies also
demonstrated that when given 10 minutes prior to PZT, approximately
10 times the oral dose of alprazolam was required to achieve
seizure suppression comparable to pulmonary delivery. While only
13% of the animals that received 0.35 mgs of particles including
alprazolam had seizures, the oral dose required to produce this
effect was 3.50 mgs.
The benefits of pulmonary delivery over oral delivery were also
evident when examining the time to seizure onset (Table 11 and FIG.
19A). The effects of oral alprazolam were again delayed relative to
pulmonary administration. As shown above, oral delivery was
markedly less effective when alprazolam was given 10 minutes versus
30 minutes before PZT. In contrast, all doses of pulmonary
alprazolam produced rapid and robust effects when given only 10
minutes prior to PZT. Not only were the effects of pulmonary
delivery more rapid, but the effective pulmonary dose was markedly
lower than the effective oral dose. For instance, when comparable
doses of alprazolam (0.35 mgs) were administered by both the oral
and pulmonary routes 10 minutes prior to PZT, pulmonary
administration resulted in seizure onset times that were nearly
maximal (>42 minutes). Oral administration of the same dose of
alprazolam, however, did not increase the latency to seizure onset
relative to control animals. In fact, oral alprazolam did not
significantly increase the time to seizure onset until the dose was
escalated to 1.75 mgs and effects comparable to those obtained with
pulmonary delivery required an oral dose that was 10 times higher
than the pulmonary dose (0.35 vs 3.50 mgs).
Similar results were also observed when quantifying the effects of
the route of alprazolam administration on the duration of the
seizure (Table 11 and FIG. 19B). Pulmonary administration exerted a
more rapid effect and also required substantially less total drug
relative to oral alprazolam. Again, oral delivery was markedly less
effective at reducing the duration of seizures when alprazolam was
given 10 minutes versus 30 minutes before PZT. Moreover, the
maximally effective oral dose, delivered 10 minutes prior to PZT,
was 3.50 mgs of alprazolam. In contrast, pulmonary delivery of only
0.088 mgs of alprazolam (nearly 40-fold lower than the maximally
effective oral dose) produced a comparable decrease in seizure
duration.
A time course analysis revealed that while the relative advantages
of pulmonary over oral alprazolam declined as the interval between
alprazolam and PZT was increased, pulmonary delivery remained as
effective as oral delivery. While oral alprazolam became
increasingly more effective as the interval between alprazolam and
PZT treatment increased from 10 to 30 minutes, the effects of
pulmonary delivery remained relatively constant over the same time
period. In fact, no differences in seizure activity were seen when
comparable oral and pulmonary doses of alprazolam were delivered 30
minutes prior to PZT. While a trend towards fewer seizures was seen
with pulmonary delivery, these differences were modest and did not
reach statistical significance (Table 11B; p>0.05). Moreover, no
statistically significant differences were observed between any
oral and pulmonary dose when comparing the time to seizure onset or
the duration of those seizures (FIGS. 20A and 11B).
FIGS. 21A and 21B further demonstrate that the effects of pulmonary
alprazolam remained relatively constant as the time between
alprazolam and PZT treatment increased. Importantly though, a
detailed analysis of the results indicated that alprazolam was
modestly more effective when the interval between alprazolam and
PZT was kept at a minimum. At each dose tested, fewer animals had
seizures when alprazolam was delivered 10 minutes vs 30 minutes
prior to PZT (although this effect did not reach statistical
significance, p>0.05). The benefit of maintaining a close
temporal relationship between alprazolam and PZT was also beginning
to emerge when examining the time to seizure onset and the duration
of seizure activity. While no differences were seen at the higher
alprazolam doses (0.175 and 0.35 mgs), animals receiving the lowest
dose of alprazolam (0.088 mgs) 10 minutes prior to PZT showed
significantly increased times for seizure onset and significantly
decreased seizure durations relative to animals treated 30 minutes
prior to PZT (FIG. 3).
TABLE 11 Effects of Alprazolam on PZT-Induced Seizures Minutes to
Duration of Animals With Seizure Seizure Route Seizures Onset
(seconds) Pulmonary 10 minutes prior to PZT Blank 12/15 (80%) 11.72
(4.63) 83.0 (26.04) 0.088 mgs 5/15 (33%) 36.71 (3.93) 7.0 (3.53)
0.175 mgs 3/15 (20%) 38.61 (3.81) 8.0 (4.3) 0.35 mgs 2/15 (13%)
42.28 (1.98) 4.0 (2.60) 30 minutes prior to PZT Blank 15/15 (100%)
9.58 (2.25) 120.13 (49.33) 0.088 mgs 9/15 (60%) 18.47 (5.50) 82.67
(33.0) 0.175 mgs 5/15 (33%) 34.05 (4.20) 16.07 (6.89) 0.35 mgs 2/15
(13%) 41.98 (2.18) 2.69 (1.90) Oral 10 minutes prior to PZT 0.35
mgs 13/15 (87%) 11.49 (3.80) 88.0 (49.22) 0.70 mgs 13/15 (87%) 9.24
(3.93) 62.07 (14.58) 1.75 mgs 7/15 (47%) 29.03 (4.41) 14.47 (4.04)
3.50 mgs 2/14 (14%) 43.37 (1.52) 5.40 (3.47) 30 minutes prior to
PZT 0 mgs 13/15 (87%) 8.75 (3.95) 96.0 (26.08) 0.088 mgs 11/15
(73%) 18.38 (4.55) 46.0 (14.48) 0.175 mgs 7/15 (47%) 33.10 (4.07)
15.0 (6.75) 0.35 mgs 4/15 (27%) 37.58 (3.50) 19.0 (12.36) Note: all
data presented for time to seizure onset and duration of seizute
are presented as mean .+-. SEM
While this invention has been particularly shown and described with
references to preferred embodiments thereof, it will be understood
by those skilled in the art that various changes in form and
details may be made therein without departing from the scope of the
invention encompassed by the appended claims.
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